Official Harrop TVS1740 Supercharger Thread

[KawBoy]

From Harrop; "We are working on stage 2 however do not have any further details".

[BPMSport]

I'll update you guys on stage II next week.

[WickedE93]

Originally Posted by Mike Benvo

I'll update you guys on stage II next week.

In for that Stage 2 update! It might just be what I need to get me to purchase this kit!

[dozaiya]

it will be next week in 2 days....i cannot wait

[BPMSport]

Had a conversation with the Harrop engineering team yesterday about Stage II.

We are working on scheduling some dyno time at higher boost levels. Stage II will not be released until it's been dyno and track tested, so it's not going to be released quickly. We took a ton of time before releasing Stage I... the same methodology will be followed with the next Stage. I'll update everyone with progress - and there will be a very reasonable upgrade path for Stage I users.

[ashtaron14]

Originally Posted by Mike Benvo

there will be a very reasonable upgrade path for Stage I users.

I'm listening

[XIX]

Hi Guys,

Anyone have any opinions on the torsional load on the crank of this setup as opposed to some of the centri ones ?

Is one better or worse or are they all the same necessary evil ?

How many miles have guys done on these kits ?

[Mvy]

Originally Posted by DrFerry

Harrop SC pulleys are in the same vertical plane as the nearest ancillary serpentine belt crank pulley. To me this means a lower moment on the crank main bearings than some of the centrifugals with belts driven off the serpentine crank pulley that is furthest away from the main bearings. That's just an opinion folklets. This is my speculation. I have no data.

Anyway, I have over 20,000 miles on my Harrop kit.

I agree that as far as superchargers go, the Harrops vertical plane is part of what makes it less stressful on the motor's mains. Its not that there is no stress, just the best design for the space. 8k miles on my kit so far. See my oil report at the top of the page.

[pbonsalb]

Aren't all S65 superchargers in line with the accessory drive in order to be driven off them?

[Properstyle]

Originally Posted by Mvy

I agree that as far as superchargers go, the Harrops vertical plane is part of what makes it less stressful on the motor's mains. Its not that there is no stress, just the best design for the space. 8k miles on my kit so far. See my oil report at the top of the page.

i'm a bit confused what is stage 2 suppose to make up? smaller pulley? or a larger displacement blower? If it is just pully wasn't someone just get a smaller pulley ordered? and have the car retuned. maybe I missing it.

[XIX]

Hey guys, just wondering why you think vertical is better than horizontal ?

I would have thought the 2d direction wouldnt make any difference as it is still a force in a direction other than through the bearing ?

I was more wondering about the actual pulley locations and tightness of the belts ? For instance if the twinscrew loads up boost easier then it would lead me to beleive the belt would not need to be as tight or need as much torque to turn it? This is what I would think would cause less stress ?

I have read that any charger that has an extended pulley (outside of the existing plane in the 3rd dimension) is the biggest issue, similar to the effect of running large spacers on wheels? That also makes sense.

[M.Hagen]

Originally Posted by Properstyle

i'm a bit confused what is stage 2 suppose to make up? smaller pulley? or a larger displacement blower? If it is just pully wasn't someone just get a smaller pulley ordered? and have the car retuned. maybe I missing it.

Stage 2 will likely consist of a new crank pulley and compensated auxiliary pulleys (to keep the auxiliary driven ratios equal), combined with a new tune/calibration. You can put this together yourself, but you wouldn't have access to the programs within the electronic bypass valve to help mitigate low-rpm knock (it appears to be a Harrop-programmed unit). The Stage-1 kit already ramps boost using the bypass valve below 3500 RPM. I suppose you can overcome this by tweaking the VANOS targets to bleed cylinder pressure through valve overlap, but that equation becomes complex when trying to achieve good throttle response at the same time.

The snout pulley is already as small as one would reasonably go to minimize belt slippage, so crank pulley is the likely 'boost-up' route.

With the current snout/crank ratio, this TVS1740 rotors are spinning just shy of 14,000 RPM at 8400 engine RPM. The unit is rated to 20,000 RPM, and based on the Eaton TVS rotor efficiency maps there is a minimal adiabatic penalty at the maximum rated RPM. The Z06 runs just shy of 20,000 RPM from the factory, so we know it is "good enough" for OE applications at max rotor speed.

I estimate there is an additional ~25-30% power to be had based on the simple math on the current rotor speed and available overhead on the TVS1740. Based on those assumptions, an E9X M3 making 500rwhp on the Stage-1 Kit should see peak numbers between 600-620rwhp with rotor speeds of 20,000 RPM.

[pbonsalb]

Probably use the bypass valve to bleed boost at lower rpm to avoid knock and protect the rods, so there might be 2-3 psi more boost at higher rpm only. I doubt the stage 2 will be sold to produce 600+ rwhp though the blower might be capable of it. I would expect more like 560 rwhp to make it competitive with a VT650 centrifugal in power but superior in torque. Water meth injection would allow more boost but more boost with more torque risks the stock rods so the tune will have to restrict low rpm boost. My guess anyway. Looking forward to the results. May help me decide to keep my car.

[JsL]

Originally Posted by pbonsalb

Probably use the bypass valve to bleed boost at lower rpm to avoid knock and protect the rods, so there might be 2-3 psi more boost at higher rpm only.
..

Why does boosting in lower rpm have more tendency to knock?

[Properstyle]

Originally Posted by M.Hagen

Stage 2 will likely consist of a new crank pulley and compensated auxiliary pulleys (to keep the auxiliary driven ratios equal), combined with a new tune/calibration. You can put this together yourself, but you wouldn't have access to the programs within the electronic bypass valve to help mitigate low-rpm knock (it appears to be a Harrop-programmed unit). The Stage-1 kit already ramps boost using the bypass valve below 3500 RPM. I suppose you can overcome this by tweaking the VANOS targets to bleed cylinder pressure through valve overlap, but that equation becomes complex when trying to achieve good throttle response at the same time.

The snout pulley is already as small as one would reasonably go to minimize belt slippage, so crank pulley is the likely 'boost-up' route.

With the current snout/crank ratio, this TVS1740 rotors are spinning just shy of 14,000 RPM at 8400 engine RPM. The unit is rated to 20,000 RPM, and based on the Eaton TVS rotor efficiency maps there is a minimal adiabatic penalty at the maximum rated RPM. The Z06 runs just shy of 20,000 RPM from the factory, so we know it is "good enough" for OE applications at max rotor speed.

I estimate there is an additional ~25-30% power to be had based on the simple math on the current rotor speed and available overhead on the TVS1740. Based on those assumptions, an E9X M3 making 500rwhp on the Stage-1 Kit should see peak numbers between 600-620rwhp with rotor speeds of 20,000 RPM.

Yeah just looked at the pics.of the top pulley it is quite small.

[M.Hagen]

Originally Posted by JsL

Why does boosting in lower rpm have more tendency to knock?

Cylinder filling happens over a longer period of time.

Because of this, if you have high loads (or positive pressure "boost") and aggressive ignition, the opportunity for pre-ignition increases; aka knock.

You can mitigate this by having low ignition targets and/or limit the load potential/boost levels.

At higher RPM, the ICE cycles happen so quickly that there is less likely to be knock with the same load/ignition variables as there is less time spent in the 'sensitive' regions of the compression/ignition cycle.

[JsL]

Originally Posted by M.Hagen

Cylinder filling happens over a longer period of time.

Because of this, if you have high loads (or positive pressure "boost") and aggressive ignition, the opportunity for pre-ignition increases; aka knock.

You can mitigate this by having low ignition targets and/or limit the load potential/boost levels.

At higher RPM, the ICE cycles happen so quickly that there is less likely to be knock with the same load/ignition variables as there is less time spent in the 'sensitive' regions of the compression/ignition cycle.

Thanks for the explanation.

[M.Hagen]

Originally Posted by DrFerry

To reduce belt slippage, I'm going to try a slightly shorter belt, made by Gates RPM for Super Charger applications, and a new OEM belt-tensioner. The one I am going to use = Gates RPM - K060744RPM - is slighly shorter than the one Harrop supplies with the kit. See the files attached and below in case they are useful for you.

Thanks for that! Cheers

[burnrbr]

Originally Posted by JsL

Thanks for the explanation.

Just to add... it is because of the greater volumetric efficiency in the mid-range. There's more time to injest air and burn the fuel which results in more heat. Our Vanos tuning strives to flatten out the torque curve where there would be a natural torque peak like other internal combustion engines. Generally speaking, torque curves mimic VE curves with static cam lift and cam timing. Adjustable cam lift and cam timing allow the tuning of the VE and the torque production of the engine. Ignition timing does play a much smaller a roll as does the air fuel ratio. Boost is another dimension on top on this.

[BPMSport]

Originally Posted by DrFerry

No. I don't think so.. Not all of them. There are two belts. An inner one and an outer one.

Some kits are not driven off of the belt closest to the block and this will put additional load on the main bearings. I've seen main bearing failures in cylinders 4 & 8 most likely attributable to this. The design of the Harrop kit reduces this as much as possible.

[spool twice]

being outside of the s/c efficiency range doesn't = no power to be had fwiw.

[XIX]

Anyone else getting a squeeling/squeeking noise from the pulley's (not sure which one lol!) at idle ?

Seems to be fine outside of idle/off throttle.