Harrop TVS86 Owners Thread

[johan]

Originally Posted by Irace86.2.0

Well Jay, we can’t all be so lucky finding tuners :-p

I can’t remember anyone else who dyno tuned their car, but I can recall someone saying the did a DT then did a dyno tune. I don’t know if they were happy or not. I haven’t heard anyone breaking engines on the dyno or having horror stories in this thread, but that doesn’t mean there aren’t people who had issues.

That was my point honestly - The usual suspects are basically the way to go now. Local dyno shops are usually a shit show.

[Kiske]

How is the bypass controlled on the harrop kit? It is electronic or simply controlled by vac/boost?

[johan]

Originally Posted by Kiske

How is the bypass controlled on the harrop kit? It is electronic or simply controlled by vac/boost?

Vac/boost, but it is a dual port so you could hook a 4-port mac to it and electronically control to reduce boost in lower gears.

[Irace86.2.0]

Originally Posted by johan

Vac/boost, but it is a dual port so you could hook a 4-port mac to it and electronically control to reduce boost in lower gears.

Or to get to boost sooner, but limit the max, right, kind of like a wastegate for a turbo? It would make for a super flat torque curve. Imagine throwing on a 21 psi pulley...

Current pulley:

2500 rpms = 0.26 bar = 3.77 psi
5000 rpms = 0.59 bar = 8.56 psi
7500 rpms = 0.88 bar = 12.76 psi

https://datazap.me/u/jirace/v8-flex-...ta=8-29&solo=8

21 psi pulley:

2500 rpms = 7 psi
5000 rpms = 14 psi
7500 rpms = 21 psi

With a boost controller acting as a wastegate...

2500 rpms = 7 psi
3750 rpms = 10.5 psi
5000 rpms = 10.5 psi
7500 rpms = 10.5 psi

This might be a good alternative for those looking for more power who don’t have access to E85, or who don’t want to upgrade the fuel system, but there would be an increase in low end torque and therefore a risk to the rods.

[johan]

Originally Posted by Irace86.2.0

Or to get to boost sooner, but limit the max, right, kind of like a wastegate for a turbo? It would make for a super flat torque curve. Imagine throwing on a 21 psi pulley...

Current pulley:

2500 rpms = 0.26 bar = 3.77 psi
5000 rpms = 0.59 bar = 8.56 psi
7500 rpms = 0.88 bar = 12.76 psi

https://datazap.me/u/jirace/v8-flex-...ta=8-29&solo=8

21 psi pulley:

2500 rpms = 7 psi
5000 rpms = 14 psi
7500 rpms = 21 psi

With a boost controller acting as a wastegate...

2500 rpms = 7 psi
3750 rpms = 10.5 psi
5000 rpms = 10.5 psi
7500 rpms = 10.5 psi

This might be a good alternative for those looking for more power who don’t have access to E85, or who don’t want to upgrade the fuel system, but there would be an increase in low end torque and therefore a risk to the rods.

Likely won't work well. In our testing, anything past a pulley that wants to put 16-18psi into the motor will over power the bypass valve and force it shut. You'll get erratic behavior, and you certainly won't be able to keep it from making full boost up top. So you won't be able to protect the motor via this method.

You might be able to use it with a "slightly" over spec'd pulley for pump gas to accomplish what you are looking for. You'd still run the risk of things going bad for you if the solenoid fails or a hose blows off (you could set a reasonable MAP limit that would throw a MIL if you go over, this might save you if you pay attention). You could play with setting things up normally closed instead of normally opened, but not sure how well that'd work with a supercharger. I ran mine normally open, so no duty meant full boost. I then used duty to lower boost, it worked really well up until the aforementioned limits.

[Kiske]

Originally Posted by johan

Likely won't work well. In our testing, anything past a pulley that wants to put 16-18psi into the motor will over power the bypass valve and force it shut. You'll get erratic behavior, and you certainly won't be able to keep it from making full boost up top.

Actually, that sounds perfect. Is it possible to adjust the bypass with a spring adjustment/shimming similar to a wg/bov can be adjusted?

[Irace86.2.0]

Originally Posted by johan

Likely won't work well. In our testing, anything past a pulley that wants to put 16-18psi into the motor will over power the bypass valve and force it shut. You'll get erratic behavior, and you certainly won't be able to keep it from making full boost up top. So you won't be able to protect the motor via this method.

You might be able to use it with a "slightly" over spec'd pulley for pump gas to accomplish what you are looking for. You'd still run the risk of things going bad for you if the solenoid fails or a hose blows off (you could set a reasonable MAP limit that would throw a MIL if you go over, this might save you if you pay attention). You could play with setting things up normally closed instead of normally opened, but not sure how well that'd work with a supercharger. I ran mine normally open, so no duty meant full boost. I then used duty to lower boost, it worked really well up until the aforementioned limits.

This doesn’t surprise me because there should be an increase in heat and maybe changes to flow or efficiency as the SC is overspining and bleeding boost at higher rpms. E85 might still be necessary, but there may still be benefits for achieving a flatter torque curve (essentially maximizing low end boost will limiting peak boost) for those who are concerned about blowing a motor, or who want to broaden the torque curve.

[johan]

I don't want to go too far down the rabbit hole on this, as you guys should do your own testing and find the limits on this platform / blower. All of my testing was done on a Honda K20.

But I'll just say this - it's not necessarily about the vacuum canister, it's about the size/shape/flow dynamics of the valve port itself. It can only flow so much air. At some point it can't relieve enough pressure and the blower overwhelms it.

[Irace86.2.0]

Originally Posted by johan

I don't want to go too far down the rabbit hole on this, as you guys should do your own testing and find the limits on this platform / blower. All of my testing was done on a Honda K20.

But I'll just say this - it's not necessarily about the vacuum canister, it's about the size/shape/flow dynamics of the valve port itself. It can only flow so much air. At some point it can't relieve enough pressure and the blower overwhelms it.

As you probably know, that's true of any wastegate too. It is called boost creep when the wastegate can't vent exhaust fast enough to limit the turbo to the desired boost, if anyone is not familiar. This is why people run external, larger and dual wastegates. It definitely would be cool to find the limit of the wastegate. I believe the valve hole diameter is visible in the picture below; I believe it is the hole in the center. It isn't huge, but it doesn't look too much smaller than say a Tial external wastegate, yet it doesn't have to vent hot gases either, so a smaller diameter would be fine.

[Kiske]

NOTE:
MY18 vehicles will require additional airbox components - $181.50 inc – Please enquire
https://www.harrop.com.au/shop/autom...-86-subaru-brz

Anyone know what this $ is going towards specifically?

[sw20kosh]

I run a 16psi pulley and control boost via throttle mapping. I target a nice flat 12 psi across the rev range.

[The Racers Line]

Originally Posted by Kiske

Anyone know what this $ is going towards specifically?

As you know, 2017+ use a different air box, this kit uses 50% of the stock 2013-2016 airbox. So it’s just the price of the new intake piece.

[Kiske]

So no revisions to the snout then, requiring the small amount of DIY grinding to clear the 2018's alternator plugs. :/

[Trefoil]

Originally Posted by sw20kosh

I run a 16psi pulley and control boost via throttle mapping. I target a nice flat 12 psi across the rev range.

Can you PM me any details? I live in high altitidues now after living at near sealevel. That sounds like a great opportunity for people who want a big engine in the stock car.