Harrop Owners Chime In!

[DrFerry]

Originally Posted by MikeYQM

Goodyear/Conti Elite part number is: 4060750 I believe Goodyear/Conti discontinued that spec in the Gatorback/Elite belt. I could only find 6pk1900G in current production. I ordered one Conti 4060750 on Amazon

Yes, I use Continental Elite part = 4060747

[DrFerry]

Originally Posted by tbuck

In for the response for belt info as well, needing to get one of these too. Also I asked Mike Benvo specifically about the plugs and possible need for a cooler model and he assured me that stock were perfectly fine for street use. I have had to use cooler plugs in other SC applications before so was curious.

Yes, I use Continental Elite part = 4060747

[DrFerry]

Originally Posted by DrFerry

As B8bydesign already mentioned, most issues are chronicled here:
https://www.m3post.com/forums/showthread.php?t=1070943

Studying that thread should give you a good feel for what others have already experienced.

Regarding your questions:

1 and 1.5: I have owned mine since late 2015 and have over 50K miles on my Harrop system. I recently encountered a bad electrical connection that was related to the poor quality of the shop installation. In my experience, there are no common bugs that I know of with the system (kit). Owners have mentioned some occasional lower speed drivability concerns, below or around the 3500RPM boost transition zone, and this is discussed in other posts. I have found this particular issue can be mitigated with throttle map selection (I use Sport). Additionally, increased E85 fuel concentration also seems to help (about E20+). The low speed drivability boost transition issue really isn't that noticeable, except occasionally when the throttle position and RPMs 'just happen' to be exactly right.

The Harrop "system" has turned out to be very robust indeed in my opinion. That being said the serpentine belt can slip if the belt tensioner is old (weak). A Gatorback style serpentine belt (Conti Elite) helped greatly reduce SC belt slippage on mine (also mentioned in the thread). One of the Harrop serpentine belt carrier bearings on my system has now become noisy (after 50K miles), but after removing and oiling, it is now much less noisy. Other owners (including me) have noticed what they thought was thermostat housing gasket coolant seepage - since the housing bolts are used in securing a carrier bracket. However, this issue turned out to be a worn header tank return hose (which needed replacing) rather than the gasket or thermostat housing itself. Overall, and in summary, the Harrop super charger system is a very robust and well-engineered kit well proven at the Nurburgring and on track.

In order to avoid any disappointment, or issues later on down the road, I recommend choosing a high quality shop and preferably one that has installed a Harrop kit before. IF that is not possible - and you are mechanically capable, then consider installing the kit yourself. Become very familiar with the installation guide before making your choice of DIY or shop selection. This is very important. See installation guide file attached.

In order to maximize your return on investment I recommend doing and/or considering most if not all of the following listed below:

A) Install an X-Pipe where the primary CATS are removed and has 200 cells per square inch (CPSI) high flow cat secondaries with resonators.
B) OR - if not A) above then Install a Catless, resonated X-Pipe
C) Replace the spark plugs with either new OEM or one heat range colder as used by G-Power and other kits (see my signature for alternative NGK Racing plug specs). I already feel the heat for blaspheming against the OEM plugs.
D) Can keep the stock OEM rear exhaust box to reduce costs if desired.
E) Replace (renew) all four oxygen sensors
F) Use a Continental Elite Gatorback serpentine pulley drive belt (see thread)
G) Use a high flow air filter like the Piper-Cross (helicopter style so I'm told)
H) Invest in some wider rear wheels; preferably 11X18 with ET 32. Put your OEM 9.5 inch wide rear wheels onto the front axle to reduce the cost of buying four new wheels.
I) To increase mechanical rear axle grip install at least 295 section width summer tires of at least UTQG Treadwear = 300 or lower. I use 295/35R18 Michelin PSS. Combine the new tires with slightly lower cold inflation pressures to increase the size (surface area) of the contact patch (the size of which is simply the load on the tire divided by its inflation pressure). With the bigger tire carcass envelope, 32 psi cold seems to work okay for me. Though I have run lower at the cost of increased shoulder wear.
J) Ensure differential oil and transmission oil are full and in good condition or relatively new.
K) Ensure your rod bearings and engine mounts are either new, low mileage and/or in decent shape.
L) Can add a couple of gallons of E85 to a full tank of 93 Octane E10 to get the most horsepower from the kit in my experience (especially in summer).

2) Regrets
A) You will spend more money on fuel
B) Tire consumption will increase
C) While using drag radials, my DCT clutch started to slip so it had to be upgraded to SSP Spec-R
D) SC whine was a bit loud for me so I blocked off the hood air box inlet and rely solely upon the front bumper air box inlet which quietened things down a bit.
E) The 14-hour time difference between the USA and Australia, but now Harrop have a U.S. Sales office in Ohio for parts (if ever needed).

3) Smiles
A) The Harrop kit will bring you many smiles. It makes the S65 V8 think it's a V10.
B) I once combined the Harrop with high grip drag radials on the street for extra giggles.
C) On cooler days (say below 45F) this kit seems to find an extra 20 or 30 horsepower…
D) Mike Benvo. He's the best for customer service and help with the system.

I've given you a lot here to think about. I hope this helps you and other people.

I'm thinking about posting a Part 2 - similar to my post above. Is there still interest in hearing more about additional Harrop ownership experiences, including the small niggles and occasional gremlins? Or not?

[tbuck]

Yes, always in for more info, certainly on something like this.

[drwankel]

Even as an owner of the kit- I enjoy reading about others experiences. Please do add a part 2.

[DrFerry]

I finally got around to posting Part 2 as a follow up to Part 1 above. So since the Harrop S65 blower kit is no longer in production, it now seems not only is the Harrop S65 kit quite the rarity, but so are the handful of Harrop equipped E9X M3s. If I had to guess I’d estimate Harrop sold less than a thousand worldwide, but that’s just pure speculation on my part. Any other data on just how rare these kits are is appreciated. Below is my list of things I’ve learned to live with about the kit since installing it in 2015, which was over 55K miles ago. Incidentally, my car turned over 120,000 miles today, and yes the rod bearings have been done with BE bearings and ARP bolts.

1) I found the rubber “snorkel” piece that connects the air box to the plenum to be a poor fit. Over the years the mouth of it ripped and was glued back to together. Since the rip is underneath the large jubilee clip it has remained airtight. Perhaps, the fit (shape) of snorkel piece was improved with later kits, but mine requires some careful finagling to line everything up correctly (airbox mouth, air filter mounting adapter, and snorkel).

2) The plenum mounts are one at each corner, if I recall correctly. If the bolts securing these mounts to the inlet manifold are ever accidentally over torqued (say by a mechanic who doesn’t have the installation manual) then the serpentine belt seems to become slightly looser as the plenum and nose pulley move a small amount downward in space. Now I know what you’re thinking; “well surely the belt tensioner will take up any slack”. Well it seems there’s a limit to how much that can actually occur. I ended up replacing my belt tensioner and installing a Continental Elite gator back belt with a slightly shorter effective length, and all of this cured the belt slippage problem that was happening (especially with drag radials installed).

3) Another oddity that occurred was when my kit was shipped from Australia the export paper work wasn’t done correctly. FedEx and U.S. Customs then hit me up for hundreds of dollars in import taxes. As it turned out the U.S. and Australia have a “free trade” agreement and therefore after some squabbles and heartache I wasn’t on the hook for tax $ after all. I recall Mr. Benvo did help out with the situation back then communicating with Harrop.

4) In the “Official Harrop” thread I posted how I had a noisy serpentine idler pulley bearing. I had originally intended to replace it, but after contacting Harrop’s office in Ohio I learned one new bearing was about ~$180. So instead the bearing was removed and re-lubricated. To do this, remove the carrier bracket, and then remove the front cover bearing seal and repack with grease or oil.

5) I wish new plugs had been included with the kit, but it turned out I went one heat range cooler anyway (it’s same plug the G-Power kit uses - see my signature for the NGK # if interested).

6) I wish a boost gage had been included with the kit. It’s not totally necessary, but would have been nice to have since when my kit was originally installed it made zero boost - due to a bad bypass valve controller ECU motherboard - which was quickly replaced by Harrop.

7) Now the main shortcoming (if you can call it that, and there are very few with the Harrop kit) is probably the same with all forced induction solutions, and that is crankcase ventilation. By this I mean, I could swear that ever since installing the Harrop it has exacerbated valve cover oil leakage and seepage. In an effort to mitigate it, I replaced both valve cover breathers - but to no avail. Under boost, I think the crankcase is under positive pressure - and so then is the air in the valve covers. This is purely my speculation and I have no data to back up this opinion. For these reasons, my next modification will be an oil catch can, as well as a new PCV valve. There are some good after market ones out there such as the Bimmerworld aluminum oil catch can.

8) Until recently, Harrop had no office in the U.S.A. This was surprising to me since Harrop makes so many kits for GM and Ford stuff. What this means is that there is no “approved” and trained installer(s) in the U.S.A. Yes, I know any mechanic worth his salt with the right tools should be able to install the kit, or any talented individual DIYer - but in my case the shop I chose was a nightmare for me and Mike B’ to coach through the install. So much so I even kept a diary of all the happenings back then. The moral of that aspect of the kit is to be very, very, careful which shop you select to install the kit - or just do it yourself.

9) Runs far too rich IMO - even with four new O2 sensors.

10) To really let the genie out of the bottle and release the Harrop kit’s full horsepower potential, remove the primary cats, and install no more than 200cpsi high flow secondary cats. Or better still go entirely cat less, but that’s loud!

Now I know there’ll be people who will want to ridicule some of the above information (there always is), which is part of the reason I rarely post here anymore. The entire M3Post E9X forum seems to get less than 100 posts a day nowadays - when back in 2008 it would get thousands of posts. So I’ll just leave this here for posterity in the hope some future, or current, Harrop kit owner finds it useful. PS: Also seee Part 1 above this.

[DRLane]

Originally Posted by DrFerry

I finally got around to posting Part 2 as a follow up to Part 1 above. So since the Harrop S65 blower kit is no longer in production, it now seems not only is the Harrop S65 kit quite the rarity, but so are the handful of Harrop equipped E9X M3s. If I had to guess I'd estimate Harrop sold less than a thousand worldwide, but that's just pure speculation on my part. Any other data on just how rare these kits are is appreciated. Below is my list of things I've learned to live with about the kit since installing it in 2015, which was over 55K miles ago. Incidentally, my car turned over 120,000 miles today, and yes the rod bearings have been done with BE bearings and ARP bolts.

1) I found the rubber "snorkel" piece that connects the air box to the plenum to be a poor fit. Over the years the mouth of it ripped and was glued back to together. Since the rip is underneath the large jubilee clip it has remained airtight. Perhaps, the fit (shape) of snorkel piece was improved with later kits, but mine requires some careful finagling to line everything up correctly (airbox mouth, air filter mounting adapter, and snorkel).

2) The plenum mounts are one at each corner, if I recall correctly. If the bolts securing these mounts to the inlet manifold are ever accidentally over torqued (say by a mechanic who doesn't have the installation manual) then the serpentine belt seems to become slightly looser as the plenum and nose pulley move a small amount downward in space. Now I know what you're thinking; "well surely the belt tensioner will take up any slack". Well it seems there's a limit to how much that can actually occur. I ended up replacing my belt tensioner and installing a Continental Elite gator back belt with a slightly shorter effective length, and all of this cured the belt slippage problem that was happening (especially with drag radials installed).

3) Another oddity that occurred was when my kit was shipped from Australia the export paper work wasn't done correctly. FedEx and U.S. Customs then hit me up for hundreds of dollars in import taxes. As it turned out the U.S. and Australia have a "free trade" agreement and therefore after some squabbles and heartache I wasn't on the hook for tax $ after all. I recall Mr. Benvo did help out with the situation back then communicating with Harrop.

4) In the "Official Harrop" thread I posted how I had a noisy serpentine idler pulley bearing. I had originally intended to replace it, but after contacting Harrop's office in Ohio I learned one new bearing was about ~$180. So instead the bearing was removed and re-lubricated. To do this, remove the carrier bracket, and then remove the front cover bearing seal and repack with grease or oil.

5) I wish new plugs had been included with the kit, but it turned out I went one heat range cooler anyway (it's same plug the G-Power kit uses - see my signature for the NGK # if interested).

6) I wish a boost gage had been included with the kit. It's not totally necessary, but would have been nice to have since when my kit was originally installed it made zero boost - due to a bad bypass valve controller ECU motherboard - which was quickly replaced by Harrop.

7) Now the main shortcoming (if you can call it that, and there are very few with the Harrop kit) is probably the same with all forced induction solutions, and that is crankcase ventilation. By this I mean, I could swear that ever since installing the Harrop it has exacerbated valve cover oil leakage and seepage. In an effort to mitigate it, I replaced both valve cover breathers - but to no avail. Under boost, I think the crankcase is under positive pressure - and so then is the air in the valve covers. This is purely my speculation and I have no data to back up this opinion. For these reasons, my next modification will be an oil catch can, as well as a new PCV valve. There are some good after market ones out there such as the Bimmerworld aluminum oil catch can.

8) Until recently, Harrop had no office in the U.S.A. This was surprising to me since Harrop makes so many kits for GM and Ford stuff. What this means is that there is no "approved" and trained installer(s) in the U.S.A. Yes, I know any mechanic worth his salt with the right tools should be able to install the kit, or any talented individual DIYer - but in my case the shop I chose was a nightmare for me and Mike B' to coach through the install. So much so I even kept a diary of all the happenings back then. The moral of that aspect of the kit is to be very, very, careful which shop you select to install the kit - or just do it yourself.

9) Runs far too rich IMO - even with four new O2 sensors.

10) To really let the genie out of the bottle and release the Harrop kit's full horsepower potential, remove the primary cats, and install no more than 200cpsi high flow secondary cats. Or better still go entirely cat less, but that's loud!

Now I know there'll be people who will want to ridicule some of the above information (there always is), which is part of the reason I rarely post here anymore. The entire M3Post E9X forum seems to get less than 100 posts a day nowadays - when back in 2008 it would get thousands of posts. So I'll just leave this here for posterity in the hope some future, or current, Harrop kit owner finds it useful. PS: Also seee Part 1 above this.

+1 on the rubber snorkel ripping. Wish there was a better replacement option. Mike is super helpful about warranty replacement although I haven't taken him up on that yet.

Would love to see your catch can solution. I intended to put something together but never got around to it.

[tbuck]

Excellent info, thank you! I am not surprised there are some issues, as the almost always is with something like this, but glad to see these mentioned now prior to my install so I know what to expect. Just a couple questions.

Originally Posted by DrFerry

2) The plenum mounts are one at each corner, if I recall correctly. If the bolts securing these mounts to the inlet manifold are ever accidentally over torqued (say by a mechanic who doesn’t have the installation manual) then the serpentine belt seems to become slightly looser as the plenum and nose pulley move a small amount downward in space. Now I know what you’re thinking; “well surely the belt tensioner will take up any slack”. Well it seems there’s a limit to how much that can actually occur. I ended up replacing my belt tensioner and installing a Continental Elite gator back belt with a slightly shorter effective length, and all of this cured the belt slippage problem that was happening (especially with drag radials installed).

Did this happen right away or at some point after install? The mounting points for my kit seem rather robust but I am wondering if there is something I can do at the outset to avoid this.

Originally Posted by DrFerry

5) I wish new plugs had been included with the kit, but it turned out I went one heat range cooler anyway (it’s same plug the G-Power kit uses - see my signature for the NGK # if interested).

I had asked Mike about this as I have used a cooler plug on upgraded SC systems in the past and was curious if that might be warranted here as well. He said the regular plug was fine and he uses them on his 600hp+ setup. What have you found to make you go with a cooler plug?

Originally Posted by DrFerry

7) Now the main shortcoming (if you can call it that, and there are very few with the Harrop kit) is probably the same with all forced induction solutions, and that is crankcase ventilation. By this I mean, I could swear that ever since installing the Harrop it has exacerbated valve cover oil leakage and seepage. In an effort to mitigate it, I replaced both valve cover breathers - but to no avail. Under boost, I think the crankcase is under positive pressure - and so then is the air in the valve covers. This is purely my speculation and I have no data to back up this opinion. For these reasons, my next modification will be an oil catch can, as well as a new PCV valve. There are some good after market ones out there such as the Bimmerworld aluminum oil catch can.

I have wondered about this as well, considering this is nearly always an issue as SC and Turbo cars age and blow-by becomes more of a concern. I recently took a very careful look at my car and there are no leaks or weeping at this time (38k miles), but a good catch can was in the plans for the future. Would be interested in your setup when you finish it.

Thanks again for your comments!

[Davisca455]

Originally Posted by tbuck

Excellent info, thank you! I am not surprised there are some issues, as the almost always is with something like this, but glad to see these mentioned now prior to my install so I know what to expect. Just a couple questions.

Did this happen right away or at some point after install? The mounting points for my kit seem rather robust but I am wondering if there is something I can do at the outset to avoid this.

I had asked Mike about this as I have used a cooler plug on upgraded SC systems in the past and was curious if that might be warranted here as well. He said the regular plug was fine and he uses them on his 600hp+ setup. What have you found to make you go with a cooler plug?

I have wondered about this as well, considering this is nearly always an issue as SC and Turbo cars age and blow-by becomes more of a concern. I recently took a very careful look at my car and there are no leaks or weeping at this time (38k miles), but a good catch can was in the plans for the future. Would be interested in your setup when you finish it.

Thanks again for your comments!

Just a little detail about the NGK R2556B-9.

They aren't just a colder version of the OEM style plug, they have a significant difference in the design.

(I'm a G-Power kit, and if you were to try these plugs in a stock engine, it will barely start, pops and farts, cranks out codes like a vending machine.)

NGK has a new part number (R2556G-9) that supersedes the R2556B-9, and is MUCH less expensive.

OEM on the Left
NGK R2556G-9 on the Right (looks exactly the same as the "B" version)

[DRLane]

Originally Posted by Davisca455

Just a little detail about the NGK R2556B-9.

They aren't just a colder version of the OEM style plug, they have a significant difference in the design.

(I'm a G-Power kit, and if you were to try these plugs in a stock engine, it will barely start, pops and farts, cranks out codes like a vending machine.)

NGK has a new part number (R2556G-9) that supersedes the R2556B-9, and is MUCH less expensive.

OEM on the Left
NGK R2556G-9 on the Right (looks exactly the same as the "B" version)

DrFerry you're using this plug without issue?

[DrFerry]

Originally Posted by DRLane

DrFerry you're using this plug without issue?

Yes, I use these plugs shown in my signature without issues. They were installed in 2017. Because they're NGK Racing Iridium they have been an install 'em and forget about-'em solution for me. See images below. I did quite a lot of research on this topic years ago. Many people "think" they have this plug when they don't IMO. Instead they install much cheaper Iridiums from some Main Street parts store and then have problems. These plugs were about $50 each! I imported mine from Japan. I kept reasonably good research records. Call NGK if needed. They designed and patented the OEM S65 Plug. Be very careful with the part number coding string. All the abbreviations mean something such as the angular bevel of the conical seat, thread pitch, crush washer, heat range and hex size. See all images attached.
.

[DrFerry]

Originally Posted by tbuck

Excellent info, thank you! I am not surprised there are some issues, as the almost always is with something like this, but glad to see these mentioned now prior to my install so I know what to expect. Just a couple questions.

Did this happen right away or at some point after install? The mounting points for my kit seem rather robust but I am wondering if there is something I can do at the outset to avoid this.

I had asked Mike about this as I have used a cooler plug on upgraded SC systems in the past and was curious if that might be warranted here as well. He said the regular plug was fine and he uses them on his 600hp+ setup. What have you found to make you go with a cooler plug?

I have wondered about this as well, considering this is nearly always an issue as SC and Turbo cars age and blow-by becomes more of a concern. I recently took a very careful look at my car and there are no leaks or weeping at this time (38k miles), but a good catch can was in the plans for the future. Would be interested in your setup when you finish it.

Thanks again for your comments!

You asked: "What have you found to make you go with a cooler plug?"

In forced induction applications the dynamic compression ratio is much higher than stock. Consequently, the stock plugs wear out (gap increases), hesitation and detonation risk increase. I learned a lot about this years ago with my 1993 late body style Twin Turbo Supra (ran Nitrous too and water alcohol mix) which ran a lot of boost. I live in the Southeast and on hot humid days the cooler plugs really helped the Supra.

Since the S65 already has something like a 10:1 compression ratio I thought the cooler plug would be cheap insurance. I've also blown up plenty of engines in other cars during my time. Besides all of the above, these iridium racing plugs don't seem to wear out. Yes, they're expensive - but so is the labor cost to keep changing (replacing) the OEM plugs in Supercharged S65 motors.

[DrFerry]

@tbuck
You asked: "Did this happen right away or at some point after install? The mounting points for my kit seem rather robust but I am wondering if there is something I can do at the outset to avoid this."

Answer:
It happened after the original install. Yes, the mounting point brackets and hardware are robust. However, I advise not over torquing the mounting bolts, as well as using a Continental Elite gator-back style serpentine drive belt to mitigate any belt slippage of the OEM four rib belt and pulley system design.

[tbuck]

Originally Posted by DrFerry

You asked: "What have you found to make you go with a cooler plug?"

In forced induction applications the dynamic compression ratio is much higher than stock. Consequently, the stock plugs wear out (gap increases), hesitation and detonation risk increase. I learned a lot about this years ago with my 1993 late body style Twin Turbo Supra (ran Nitrous too and water alcohol mix) which ran a lot of boost. I live in the Southeast and on hot humid days the cooler plugs really helped the Supra.

Since the S65 already has something like a 10:1 compression ratio I thought the cooler plug would be cheap insurance. I've also blown up plenty of engines in other cars during my time. Besides all of the above, these iridium racing plugs don't seem to wear out. Yes, they're expensive - but so is the labor cost to keep changing (replacing) the OEM plugs in Supercharged S65 motors.

Good info, thanks! I had found similar problems with my modded R53 and had always run a cooler plug in it. Since I had planned for plugs to be changed every 10k miles it will likely be a while before I need to do them again but will definitely get a set of these next time. The fact that they don't wear out will more than pay for themselves over time. This car will never see a track as it is just my garage queen, but longevity is one of the things I am trying to achieve with what minimal mods I am doing.

Originally Posted by DrFerry

@@[tbuck]
You asked: "Did this happen right away or at some point after install? The mounting points for my kit seem rather robust but I am wondering if there is something I can do at the outset to avoid this."

It happened after the original install. Yes, the mounting point brackets and hardware are robust. However, I advise not over torquing the mounting bolts, as well as using a Continental Elite gator-back style serpentine drive belt to mitigate any belt slippage of the OEM four rib belt and pulley system design.

Ok, will do. And I did manage to find a couple Gatorback belts, though I went with the original Harrop size. They seem to be hard to find for some reason now, which is why I got 2. Thanks again for your passing along of your experience with this kit. Makes me happy to know I should be able to get many years of service from this setup.

[ygoz]

Originally Posted by DrFerry

I finally got around to posting Part 2 as a follow up to Part 1 above. So since the Harrop S65 blower kit is no longer in production, it now seems not only is the Harrop S65 kit quite the rarity, but so are the handful of Harrop equipped E9X M3s. If I had to guess I’d estimate Harrop sold less than a thousand worldwide, but that’s just pure speculation on my part. Any other data on just how rare these kits are is appreciated. Below is my list of things I’ve learned to live with about the kit since installing it in 2015, which was over 55K miles ago. Incidentally, my car turned over 120,000 miles today, and yes the rod bearings have been done with BE bearings and ARP bolts.

You are wrong regarding the kit not being in production anymore, it simply stopped being imported to the US due to CARB compliance. Harrop is still making them and has no plans to stop production at the is stage.

[DrFerry]

Originally Posted by gozmanyoni

You are wrong regarding the kit not being in production anymore, it simply stopped being imported to the US due to CARB compliance. Harrop is still making them and has no plans to stop production at the is stage.

gozmanyoni Oh that's good news. Thank you for the correction. My information came from Mike Benvo's post earlier this year. Mike is the official and exclusive importer for the Harrop kit in the USA.

https://www.bimmerpost.com/forums/sh...php?p=27387420
.

[Ashley_rj]

Very happy with mine, can certainly get sideways on the motorway if it's cold though, so worth being aware of that before you boot it!!

[tbuck]

This was down the page from Mikes original post about this issue. Totally understandable but still sucks for us in the US.

Originally Posted by drwankel

Well- I think I have found the answer here. It's the impending EPA clampdown on performance parts. I sent an e-mail to harrop trying to get clarification about the situation. The short story is the kit is NOT ending production, but they are PAUSING sales in the US market.

"Thanks for the feedback on your supercharger kit I’m glad to hear you are still enjoying it and plan on doing so for many years to come. Due to current regulations in the emissions space in the USA we are pausing sales on new kits and evaluating emission requirements. This kit will still be sold to the rest of the world and parts will continue to be available and can be sourced directly from Harrop USA. Please let me know if I can help assist you with any thing further. "

If you want to keep being able to purchase performance parts- I'd highly encourage you to sign this. There entire performance market is at risk right now. Link below to send mail to your senators and representatives:

https://www.sema.org/epa-news

[DrFerry]

Originally Posted by tbuck

This was down the page from Mikes original post about this issue. Totally understandable but still sucks for us in the US.

tbuck and drwankel Thanks for the clarification and correction. It appears other parts of the world will still get to enjoy the Harrop E9X TVS kit after all. That's good to know.

[drwankel]

DrFerry How many miles do you have on those plugs? You mentioned they were installed in 2017, so I'd imagine quite a bit.

Haven't done plugs yet with the supercharger, but I've got about 5k on the kit now so its probably close to time. The really short spark plug change interval with supercharging isn't something I was thrilled about. Would be great if I could get back to a 30K interval.

Are these plugs fine to run for a street only car, and one that is not always in hot weather? It gets cold here in the winter, usually likes to hang around slightly above freezing for a few months.

Also- hows your idle with these plugs?

[DrFerry]

Originally Posted by drwankel

DrFerry How many miles do you have on those plugs? You mentioned they were installed in 2017, so I'd imagine quite a bit.

Haven't done plugs yet with the supercharger, but I've got about 5k on the kit now so its probably close to time. The really short spark plug change interval with supercharging isn't something I was thrilled about. Would be great if I could get back to a 30K interval.

Are these plugs fine to run for a street only car, and one that is not always in hot weather? It gets cold here in the winter, usually likes to hang around slightly above freezing for a few months.

Also- hows your idle with these plugs?

The plugs were installed at 86K and the car just turned over 120K. So 34K on the plugs so far. My car is used as a street car. Greenville, SC has some cold months too with ambient temps around freezing or sometimes below. One morning in 2018 I think the temperature dropped to single digits around 8F and the car started and ran just fine. The idle for the first 15 seconds or so was "lumpy" but it cleared almost immediately. I checked my records and when I imported the plugs from Japan they cost $48 each not $80 as I said before - though they're probably higher today.

This topic of spark plugs on this particular forum has "chased" many a person away due the passionate outbursts of many who I am convinced were using off the shelf NGK Iridiums with a very different design. Spark plug technology - while a mature industry - is reasonably sophisticated. Hence, the micro and macro design has big effects. Anyway, I run them in hot and cold weather (at least SC cold weather), damp weather, and even with E30 or higher sometimes and have had zero issues whatsoever. I can already hear the naysayers due to the blasphemy...

It idles fine. Would be happy send sound file.

PS: Links
Colder Heat Range (9) Plug I use:
https://www.ngk.com/ngk-4962-r2556b-9-racing-plug

Same Plug with OEM Heat Range (8)
https://www.ngk.com/ngk-6453-r2556b-8-racing-plug

New NGK plug that replaces the one I use (price has dropped to $27..)
https://www.ngk.com/ngk-93253-r2556g-9-racing-plug

NGK Article
https://www.ngk.com/how-do-i-find-a-...-hotter-plug-3

[drwankel]

Thanks! Good to hear. I should probably give these a shot. Regarding prices, these are for the R2556G-9, which apparently is the successor to the R2556B-9 as someone mentioned above. Prices are pretty reasonable.

30 bucks from Summit:

https://www.summitracing.com/parts/ngk-93253

$25.12 from NGK directly:

https://www.ngk.com/ngk-93253-r2556g-9-racing-plug