Harrop twin screw sc for s65

[///Matthew]

Originally Posted by saxonb

From Autozine:

Thanks for the info!

[S65]

The tune was not completed when Bimmerfest was going on. I heard the car had to be driven at low rpm so it wouldn't blow up. Im sure they need more time to really do the proper r&d on it but I wouldn't want to be first in line to buy a kit.

I heard this first hand so a little birdy didnt tell me.

[///Matthew]

Originally Posted by S65

The tune was not completed when Bimmerfest was going on. I heard the car had to be driven at low rpm so it wouldn't blow up. Im sure they need more time to really do the proper r&d on it but I wouldn't want to be first in line to buy a kit.

I heard this first hand so a little birdy didnt tell me.

It certainly would have been a shame if that car blew up...

[S65]

Originally Posted by ///Matthew

It certainly would have been a shame if that car blew up...

I agree. Your from new york or something right? Brand new m3 and never even drove it.

[chris s]

Is it tuned and running properly now?

[Richbot]

Boost can be controlled on an SC, except you vent and recirculate excess compressed air instead of the nonexistent turbine side like a wastegate would. The "fixed" flow available from a given blower at a given rpm does not have to all be crammed into the engine, at part throttle and even WOT at low RPM, most OEM and aftermarket systems are bypassing.

[S65]

Originally Posted by chris s

Is it tuned and running properly now?

A youtube dyno video would be awesome.

[Longwong]

This is one thing I really do not get other than if I were a company or a enthusiast who simply wanted to do it just to see if it could be done. For the buyer however I ask why? I would argue one of the best or most characteristic parts of the m3 has been the high revving linear power curve peaking near redline with instant throttle response. It is so perfect to modulate the throttle and keep it above 7k on the track. I understand a supercharger such as ESS and the like as they accentuate the power curve that is already there but do not at all change the character of the high-revving power model.

But if this now turns the s65 engine into a "big V8" so to speak, with a lot of low end torque and than the power actually will probably be more like the 335 or a turbo car and there will be no need to rev it up past 7500. This to me is exactly what a c63 is. The newest version handles as well as the m3 and it has a big v8.

Or a tuned 335 would be perfect.

I don't know, I Just don't know why a m3 owner would throw away the perfect linear powercurve that is a lower torque/high redline delivery of power. As is often argues, engine torque is one way to lay down thrust at the wheels but so is High-rpms with gearing and the wheels don't care which one it is as they go just as well with either method. We have a unique method of making the power in the m3 and this changes it. Not for me.

Better yet I would just get the new f80 as this will be exactly what this is trying to be but then keep the e92 for what it is.

[THE TECH]

Originally Posted by Longwong

This is one thing I really do not get other than if I were a company or a enthusiast who simply wanted to do it just to see if it could be done. For the buyer however I ask why? I would argue one of the best or most characteristic parts of the m3 has been the high revving linear power curve peaking near redline with instant throttle response. It is so perfect to modulate the throttle and keep it above 7k on the track. I understand a supercharger such as ESS and the like as they accentuate the power curve that is already there but do not at all change the character of the high-revving power model.

But if this now turns the s65 engine into a "big V8" so to speak, with a lot of low end torque and than the power actually will probably be more like the 335 or a turbo car and there will be no need to rev it up past 7500. This to me is exactly what a c63 is. The newest version handles as well as the m3 and it has a big v8.

Or a tuned 335 would be perfect.

I don't know, I Just don't know why a m3 owner would throw away the perfect linear powercurve that is a lower torque/high redline delivery of power. As is often argues, engine torque is one way to lay down thrust at the wheels but so is High-rpms with gearing and the wheels don't care which one it is as they go just as well with either method. We have a unique method of making the power in the m3 and this changes it. Not for me.

Better yet I would just get the new f80 as this will be exactly what this is trying to be but then keep the e92 for what it is.

The reason someone would likely buy this is that the majority of drivers use their cars on the street. The street is where the M3 shows it's flaws. Hard to use high revs driving light to light. A supercharger like this would be the perfect compliment to a daily driver. No more high revving to get power on the street. I think it's a fantastic idea!

[Longwong]

Originally Posted by THE TECH

The reason someone would likely buy this is that the majority of drivers use their cars on the street. The street is where the M3 shows it's flaws. Hard to use high revs driving light to light. A supercharger like this would be the perfect compliment to a daily driver. No more high revving to get power on the street. I think it's a fantastic idea!

I guess that is my point. Why get the m3 in the first place or if you have it why not replace it with the new f80 which will be out by the time this goes mainstream or pick up a used c63 amg which is a perfect motor for low end grunt lovers. It takes a high-revving top end power motor and turns it into something that is not. If there was not new f80 coming with turbos stock, no competition like the c63 to offer a package with low end torque than I could see this but not sure who would pay for this. I am sure many will but I just personally don't understand it.

[THE TECH]

Originally Posted by Longwong

I guess that is my point. Why get the m3 in the first place or if you have it why not replace it with the new f80 which will be out by the time this goes mainstream or pick up a used c63 amg which is a perfect motor for low end grunt lovers. It takes a high-revving top end power motor and turns it into something that is not. If there was not new f80 coming with turbos stock, no competition like the c63 to offer a package with low end torque than I could see this but not sure who would pay for this. I am sure many will but I just personally don't understand it.

Isn't that the same as saying, "why do you need a supercharger in the first place?" or "why do you need to mod this already good car?".

[esquire]

what's the update on this?

[Top_Gear]

I would also like to know if this SC kit is more of hobbyist group's research activity or if it is a serious and credible engineering effort toward the development of a real product for the streets coming from a dedicated and well funded product-oriented company. Sorry guys but I am still not clear on what this is yet.

[BPMSport]

Originally Posted by Top_Gear

I would also like to know if this SC kit is more of hobbyist group's research activity or if it is a serious and credible engineering effort toward the development of a real product for the streets coming from a dedicated and well funded product-oriented company. Sorry guys but I am still not clear on what this is yet.

I think you should do some research on what Harrop has built in the past. They make kits for a number of different vehicles and even work with OEM's. It's not a bunch of boys building a kit in their back yard.

[Longboarder]

Originally Posted by THE TECH

Isn't that the same as saying, "why do you need a supercharger in the first place?" or "why do you need to mod this already good car?".

I think what he was trying to say is that a positive displacement blower dramatically changes the characteristics of the S65 powerband.

Now compare that to the powerband of a stock S65 vs a blown S65 produced by the current centrifugal offering (see my dyno attached) which simply provides an enhancement of the S65's existing powerband.

[Longwong]

Exactly LB. There becomes a point when if you are now going to change the power curve of the engine into a curve that feels more like a tuned 335 or a big v8 than what is the point of having the m3 other than if you are someone who bought and m3, own it and financially makes sense to do this rather than buy a 335 or c63 now.

It also is not hard to rev in my view day to day. I simply keep the gears relatively low when accelerating or shifting down. If I just need to keep up with traffic than the power available at the low rpms is more than enough to cruise with traffic. If I want to let her rip than I drop a couple gears. Its really not hard. But beside the point, why would anyone want to change the character of this engine? Go buy a different car as once you change the s65 character it changes the purpose of this engine and car. As I said I would do it as a project car to see if it could be done but honestly guys, anyone that has some history with Roots type SC knows that its SO not realistic to have a 8400 rpm car use this unless you make sure you never rev it past 6k rpm. In that case it really boggles my mind why you would do this. This type of SC simply does not make for linear power delivery and at high rpm it will be consuming over 150 hp likely given its inefficiency, let alone inefficiency over 7k rpms. Heat will be unreal and this simply will drive like a 335, nothing more. The 7-8400 range will be so unaccessible or bad for longevity that I will tell you this will never be a solution for anyone unless they truly want a 335 powerplant in their m3.

[Top_Gear]

Originally Posted by Mike Benvo

I think you should do some research on what Harrop has built in the past. They make kits for a number of different vehicles and even work with OEM's. It's not a bunch of boys building a kit in their back yard.

Excuse my ignorance on these guys but I am not sure this video is evidence that they know what they are doing with high-RPM engines from BMW. It looks like they like supercharging big block V8's and particularly those from GM. The M3 engine maybe too big a challenge and I can't see how they avoid spending many years of street testing to get a reliable product to the M-customer.

[phrozen06]

Originally Posted by Top_Gear

Excuse my ignorance on these guys but I am not sure this video is evidence that they know what they are doing with high-RPM engines from BMW. It looks like they like supercharging big block V8's and particularly those from GM. The M3 engine maybe too big a challenge and I can't see how they avoid spending many years of street testing to get a reliable product to the M-customer.

[BPMSport]

Originally Posted by Top_Gear

Excuse my ignorance on these guys but I am not sure this video is evidence that they know what they are doing with high-RPM engines from BMW. It looks like they like supercharging big block V8's and particularly those from GM. The M3 engine maybe too big a challenge and I can't see how they avoid spending many years of street testing to get a reliable product to the M-customer.

Harrop has an RS4 Kit that spins to 8,500 RPM which is sold by APR. They also supply superchargers to OEM's such as Lotus.

They have been in business for 55 years, I doubt it's their first rodeo.

You're entitled to your opinion but I think they deserve a bit more credit than that. Hardware wise the kit is very promising.

This kit when complete will also "simply provide an enhancement of the S65's existing powerband". In fact, since boost is not rising linearly with RPM like with a centri, it will probably mimic the stock M3 curves even more so.

[///Matthew]

Originally Posted by Mike Benvo

Harrop has an RS4 Kit that spins to 8,500 RPM which is sold by APR. They also supply superchargers to OEM's such as Lotus.

They have been in business for 55 years, I doubt it's their first rodeo.

You're entitled to your opinion but I think they deserve a bit more credit than that. Hardware wise the kit is very promising.

This kit when complete will also "simply provide an enhancement of the S65's existing powerband". In fact, since boost is not rising linearly with RPM like with a centri, it will probably mimic the stock M3 curves even more so.

Well put Mike.

[BuckRodgers]

Originally Posted by Top_Gear

Excuse my ignorance on these guys but I am not sure this video is evidence that they know what they are doing with high-RPM engines from BMW. It looks like they like supercharging big block V8's and particularly those from GM. The M3 engine maybe too big a challenge and I can't see how they avoid spending many years of street testing to get a reliable product to the M-customer.

The problem for Harrop is that they are hardware engineers not software. Building hardware for any application is the easy part, making it work is the hard part. Without in house tuning on a complex design like this they are asking for trouble. Their best bet would be to sell the hardware to someone who can actually make it work. Trying to farm the tuning out to an unknown 3rd party so they can sell it under their name is a big no no. Im also not sold that the S65 is a good platform for positive displacement unless you control the boost early, in which case you might as well buy a centrifugal.

Im going to assume with no updates from the owner of the car they are using as a test mule that there is still no tuning for this hardware. Even with a working test file you would need months of testing before handing a product like this to the public and it would need to be proven to have some advantage over the current available options.

[VCMpower]

Originally Posted by ///Matthew

Well put Mike.

+1