Forged Engine & Stage 4 AVO Turbo

[ChrisD]

Got it on the dyno last weekend and as you can see peak power at the flywheel was 335 bhp and 275 lbs ft of torque, which is quite a bit less than we were expecting.

Considering someone else with the stage 3 turbo running 0.8 bar of boost got 325 bhp (not sure if that was on a different dyno though) it seems odd that stage 4 turbo running 1.2 bar of boost would only be 10 bhp more. The stage 3 run was on stock compression ratio whereas I'm on 10:1, but surely the extra boost should easily make up for that and then some. Of course this is only peak power, its possible mine is making more power elsewhere in the rev range but I don't have a graph of the stage 3 to compare to.

Fensport suggested that perhaps the tyres were slipping on the dyno as this seems like a very low figure to them for the setup I'm running. We did have issues with the tyres spinning at first but the guys running the dyno strapped the rear subframe down and said they were happy that the tyres weren't spinning after that. Fensport did also say when they mapped it that they could push it and probably get another 20 bhp out of it but that they'd rather keep things safe especially as I'm going to be bouncing it off the limiter at drift days every now and then (thrashed it at a drift event just 2 days ago and it survived).

Regardless of the numbers, I'm happy as it pulls really well now - definitely noticeably faster than it was before with 0.8 bar on the stock engine. Everyone that I took out for a spin at the GT86 dyno day was shocked at how fast it was so I guess that's a good sign lol spins the wheels up easily as well and that's what I wanted.

Next job is getting an extra set of calipers mounted to the rear so we can get the hydraulic handbrake working, and also fitting a 1.5 way LSD. Fun times

[drewhusaf27]

That's awesome man! Thanks for the post the suspense was killin me waiting to see how it did. I did also expect it to do better on stage 4 than that though. Let us know what you find out!


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[spitfire481]

something doesn't seem right. i made 300whp on regular pump gas with a base avo kit around 11psi. 400whp at 18psi on e85. even with the compression drop, 17psi with the slightly larger avo turbo i feel should make way better than it did. either way, glad you got it all sorted out and running right again. numbers don't really mean a lot anyway, its how it feels

[ChrisD]

Originally Posted by spitfire481

something doesn't seem right. i made 300whp on regular pump gas with a base avo kit around 11psi. 400whp at 18psi on e85. even with the compression drop, 17psi with the slightly larger avo turbo i feel should make way better than it did. either way, glad you got it all sorted out and running right again. numbers don't really mean a lot anyway, its how it feels

Yeah that's what we were saying, people seem to make this much with way less boost and on the lower stage turbo kits, so it does seem a bit odd. Fensport also said when they mapped it and logged everything they didn't see any kind of drop off in torque towards the top end like there is on the dyno graph.

So I dunno, I could probably get better numbers if I went on a different dyno and put better tyres on and had some more weight over the rear etc etc, but I'm not bothered about dyno numbers enough to do that. It drives great now so its all good

[drewhusaf27]

That's all that matters is the you are happy with how the car drives. Numbers are all that matter to some people.


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[s2d4]

US dyno vs the world.
Their dynos read a lot higher

[totopo]

Originally Posted by ChrisD

Considering someone else with the stage 3 turbo running 0.8 bar of boost got 325 bhp (not sure if that was on a different dyno though) it seems odd that stage 4 turbo running 1.2 bar of boost would only be 10 bhp more. The stage 3 run was on stock compression ratio whereas I'm on 10:1, but surely the extra boost should easily make up for that and then some. Of course this is only peak power, its possible mine is making more power elsewhere in the rev range but I don't have a graph of the stage 3 to compare to.

0.8 bar @ 12.5:1
You are running 11.6 PSI of boost at an altitude of 0 feet. Your motor's static compression is 12.5 :1. At this boost level and altitude your effective compression ratio is 22.36 :1.

1.2 bar @ 10:1
You are running 17.4 PSI of boost at an altitude of 0 feet. Your motor's static compression is 10 :1. At this boost level and altitude your effective compression ratio is 21.84 :1.

[ChrisD]

Originally Posted by totopo

0.8 bar @ 12.5:1
You are running 11.6 PSI of boost at an altitude of 0 feet. Your motor's static compression is 12.5 :1. At this boost level and altitude your effective compression ratio is 22.36 :1.

1.2 bar @ 10:1
You are running 17.4 PSI of boost at an altitude of 0 feet. Your motor's static compression is 10 :1. At this boost level and altitude your effective compression ratio is 21.84 :1.

If its that simple then wouldn't the car be making less power now than it was before?

[Tim Radley]

That's pretty low power for the spec like you say and that turbo looks nasty and laggy for the power. Power coming in at that rpm on most other 2.0 engines I build are all making 700+bhp
What compression and leakdown figures did you get? Just thinking maybe there is an issue there.
What is your oil consumption like now and is the catch can filling with oil?
Why is the boost so low, surely you could easily run 2 bar now?

[Nigelr32]

Just a thought Chris, You have a Stage 4 now, but not the bigger pipework that the kit comes with? Didn't you also mention Adrian had "tuned" this turbo?

[ChrisD]

Originally Posted by Nigelr32

Just a thought Chris, You have a Stage 4 now, but not the bigger pipework that the kit comes with? Didn't you also mention Adrian had "tuned" this turbo?

nah I got the larger intercooler pipes etc installed at the same time as the stage 4 turbo. Yeah they've tweaked this turbo to give slightly more bhp at the top end. Fensport said in their logs they don't see the air flow or anything dropping off towards the top like the torque does on the dyno so that's another thing that makes them think maybe the wheels were slipping.

[ChrisD]

Originally Posted by Tim Radley

That's pretty low power for the spec like you say and that turbo looks nasty and laggy for the power. Power coming in at that rpm on most other 2.0 engines I build are all making 700+bhp
What compression and leakdown figures did you get? Just thinking maybe there is an issue there.
What is your oil consumption like now and is the catch can filling with oil?
Why is the boost so low, surely you could easily run 2 bar now?

I don't think this turbo will give anywhere near 2 bar of boost. Fensport said the most they got out of it was about 1.3 when they were using it on their car (race fuel, stock engine internals) and even on the stage 5 that they've just started testing they can only run 1.5 bar so far.

I've not seen dynos from other people using different turbos on a GT86 but I thought it was pretty normal for the power to start kicking in at about 4K RPM on a turbo GT86 (especially now that I'm on 10:1 CR pistons).

Like I said before, they did say they could push it further but I'd asked them to keep it as safe and reliable as possible because its going to be sitting bouncing off the limiter on drift days quite a lot.

Lets face it whatever the dyno results were, someone would be on here saying they could have tuned it better etc etc. I do think the dyno results are a bit misleading and that the tyres might have been slipping, but I don't care about dyno figures enough to go prove that just to satisfy people on a forum. At the end of the day I wanted it to be faster but still reliable, and that's what I've got. So I'm happy

[Nigelr32]

Originally Posted by ChrisD

Lets face it whatever the dyno results were, someone would be on here saying they could have tuned it better etc etc. I do think the dyno results are a bit misleading and that the tyres might have been slipping, but I don't care about dyno figures enough to go prove that just to satisfy people on a forum. At the end of the day I wanted it to be faster but still reliable, and that's what I've got. So I'm happy

Good on ya mate!! Enjoy!!

[sam69]

Just wondering if you have any oil psi readings with the Reimax gears as I've seen people saying they give less pressure at lower revs and that they aren't worth putting in ?

Would like to hear your opinion on this ChrisD or anyone with the Reimax gears .