Harrop TVS86 Owners Thread

[Dipstik-sportech]

So has anyone gone north of 400whp with this kit yet?

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[armstrom]

Originally Posted by Dipstik-sportech

So has anyone gone north of 400whp with this kit yet?

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I don't know of anyone having done so with the harrop. I know of one person who made 420RWHP with the edelbrock kit on a built motor and E85. Since the edelbrock kit uses the same Eaton screws as the Harrop I would imagine it's possible. But only just.
-Matt

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[The Racers Line]

Originally Posted by Dipstik-sportech

So has anyone gone north of 400whp with this kit yet?

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Coming soon.....

[CSG Mike]

Originally Posted by armstrom

Can you elaborate a bit on how a header is built for forced induction? I understand the changes you would make for a turbo manifold (shorter runners for faster spool, divided/undivided flange, wastegate plumbing, etc...) but I've never heard such things applied to a supercharger build. My understanding is that generally superchargers will respond to exhaust mods in a similar way to NA.
-Matt

There are FI specific Ace headers available for folks who have fully built heads, that use larger runners to accommodate larger exhaust volume.

That same header would *lose* power on a NA car because the exhaust velocity will be too low due to the increased volume of the header.

http://counterspacegarage.com/ace-anaconda-48-gt86.html

[CSG Mike]

Originally Posted by armstrom

From what I can tell the 350 is not available any more. CSG has them listed but they are priced almost $300 more than the CS400. The ACE web site doesn't even list it any more.
-Matt

The A350 is available exclusively through CSG.

[Dipstik-sportech]

Might sell off my turbo stuff and switch if I can get around 450whp with a twin screw and I really like this kit.

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[armstrom]

Originally Posted by Dipstik-sportech

Might sell off my turbo stuff and switch if I can get around 450whp with a twin screw and I really like this kit.

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I don't know that I would do that. You really can't run more than ~16-17 PSI on this kit due to the minimum pulley size available (65mm I believe). From your signature it appears you have a built motor with only 9.5:1 compression. That may not let you break into 400RWHP even with E85. That's the main downside with this kit, you just can't crank the boost up very high. Plus you will only make that boost at the top of your RPM range rather than having a turbo that can spool at ~3000RPM and hold the same boost through the entire rev range.
-Matt

[Dipstik-sportech]

Originally Posted by armstrom

I don't know that I would do that. You really can't run more than ~16-17 PSI on this kit due to the minimum pulley size available (65mm I believe). From your signature it appears you have a built motor with only 9.5:1 compression. That may not let you break into 400RWHP even with E85. That's the main downside with this kit, you just can't crank the boost up very high. Plus you will only make that boost at the top of your RPM range rather than having a turbo that can spool at ~3000RPM and hold the same boost through the entire rev range.
-Matt

Actually positive displacement blower make they're peak boost low and sometimes taper off at high rpm. Centrifugal superchargers are like that though. The reason most of our engines can't make power is the 12.5:1 comp ratio, lowering it allows more boost but with a turbo it creates more lag but with a twin screw supercharger there is no real lag.

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[Dipstik-sportech]

The limit to power is the amount of air the blower can flow not the max psi.

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[armstrom]

Here's a chart of a 3rd gear WOT datalog on my system with the stock 95mm pulley.
http://www.datazap.me/u/armstrom/3rd...a=2-6-8&solo=8

Yes, it comes into positive pressure pretty much as soon as the bypass valve closes. But at 2700 RPM I'm only making .2 bar of boost (~3 PSI) Boost continues to climb throughout the entire pull until it hits a peak of .6 bar (8.9 PSI) at 7075 RPM... I ran out of road so I didn't rev to the limit....

PD blowers come on boost more quickly than centrifugal blowers, yes... but that doesn't mean boost doesn't build over the RPM range. A well sized turbo may be able to hit my peak of 9PSI before 3000RPM and then hold it throughout the entire rev range. That would yield more area under the curve and a faster accelerating car. Peak numbers can be misleading. Don't get me wrong, I really enjoy my Harrop kit but the power delivery is very different than a turbo car. Throttle response is pretty much instant but the power builds linearly rather than hitting hard like a turbo would.
-Matt

[Bfranklyn86]

Originally Posted by Dipstik-sportech

Might sell off my turbo stuff and switch if I can get around 450whp with a twin screw and I really like this kit.

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This kit made 428whp on e85with the HKS 2.1l stroker kit (stock compression ratio) and a larger throttle body - 19psi

I'm not sure how you'd get 450whp. I don't know of anyone in the TVS1320 community who's dropped the compression on an engine build. I remember cosworth's Matt saying he thought a slight drop to 11:1 would be optimal for a twin screw set up. Maybe that's the way forward.

One thing to consider if you swap is that you'll not make much power on 91.

[armstrom]

Originally Posted by Dipstik-sportech

The limit to power is the amount of air the blower can flow not the max psi.

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Yes, this is true. The blower, being a PD pump, will move a fixed volume of air every time it rotates (if you ignore pumping losses due to pressure ratio). If the engine doesn't consume all of the air volume that the blower moves then the result will be an increase in boost pressure in the manifold.
Since superchargers typically do not have any method of closed-loop boost control like turbos do that means even at a steady state (load the engine so that a given throttle input does not result in an increase in RPM) the boost will still build over time even without an increase in RPM until it hits equilibrium due to a drop in pumping efficiency as the pressure ratio increases.
-Matt

[armstrom]

Originally Posted by Bfranklyn86

This kit made 428whp on e85with the HKS 2.1l stroker kit (stock compression ratio) and a larger throttle body - 19psi

I'm not sure how you'd get 450whp. I don't know of anyone in the TVS1320 community who's dropped the compression on an engine build. I remember cosworth's Matt saying he thought a slight drop to 11:1 would be optimal for a twin screw set up. Maybe that's the way forward.

One thing to consider if you swap is that you'll not make much power on 91.

I still think a lower CR build would be better for this kit if you only have access to pump gas. A 10:1 or so ratio would probably be safe enough with the smallest pulley size. Running the small pulley on a stock CR engine requires either the use of E85 (which will make ~400RWHP) or taking out a TON of timing (and probably significant changes to valve timing) in order to keep the engine safe... That same engine, at the same boost only made ~270RWHP on 91 vs 420 RWHP on E85.

If you have lots of E85 available locally then by all means, stick with the stock CR and get big power. But for me, a better compromise is to have a lower CR and still make mid 300s at the wheels on pump gas. I only know of one E85 station anywhere near me and that would involve a 45min round trip just to fill up... not convenient. Of course, I've never seen any dyno plots of this configuration so it's pure speculation on my part for now

-Matt

[Dipstik-sportech]

Yeah im looking for more low end torque. A pd blower will out pull most turbos until about 4500rpm which is where most people drive daily. Don't get me wrong the rush of 500+whp is fun but around town it's a dogs breakfast. I know boost builds over rpm but it builds it miles quicker than any other form of boost. I just don't wanna sell all my shit then be limited to like 350hp.

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