Turbo Help!

[MrMuddle]

Hi All, wonder if you can help. I'm currently making just over 300whp on my Euro M52B28, stock engine, homebuilt log manifold(not the best), 3" downpipe and full 3" system, M50 inlet manifold, Ebay GT35 turbo and running 13psi. Intercooler has a 3" core, 2.25" hot side pipes and 3" cold side.

Looking at most builds on here, I'm probably over 100whp down on what you guys are running at lesser boost levels and I'm just wondering if it's down to the cheap turbo or my badly designed turbo manifold, or if maybe you're running way more advance than me?

To give you an idea on what ignition advance I'm running, it goes from about 10* at 3900rpm to 12* at 6500rpm in my 180kpa row. I do need to get a new timing light as I'd like to check timing isn't dropping off ridiculously at high rpm, but its all been checked at idle so my trigger angle etc is correct. AFR's in boost are about 11.6. I've been looking at Water/Meth injection as I am definitely knock limited as if I try to run more advance or lean out my AFR's into the 12's it'll start knocking around 4500 and 5500rpm.

I know there's lots of different factors when it comes to making power, but I guess I'm wondering if people have experience with the Ebay turbo's making good power. I've been considering changing to a Holset HX35 or HX40 or a S2X series Borg Warner if I could pick up one cheap enough.

Power goals wise, really I'd like to be around 400whp if the stock M52B28 will take it and I don't really want to open the engine.

Budget is as small as possible, as I'm just about to start a build on my E46 compact!

Any advice would be greatfully received and thanks in advance.
Rob

[pbonsalb]

What is the fuel? Stock cams? What turbine housing size? Internal or external gate? What are the core dimensions of the IC — you provided only thickness? What kind of dyno have you just over 300 rwhp?

[MrMuddle]

Fuel is UK 99, not sure if that's your 93 in the US?
Yeah stock cams, engine is untouched.
Turbine specs are 0.63 A/R, 68mm inducer diameter and 62.4mm exducer diameter. Compressor side is 0.7 A/R, 61.5mm inducer and 81.5mm exducer.
External wastegate, think its 38mm iirc.
Intercooler is 600x300x76 iirc.
The dyno was a Mainline Dynolog Chassis dyno. Car made 300.4rwhp at 5825rpm and 275ftlb at 5631rpm.

[et89]

Fuel is UK 99, not sure if that's your 93 in the US?
Yeah stock cams, engine is untouched.
Turbine specs are 0.63 A/R, 68mm inducer diameter and 62.4mm exducer diameter. Compressor side is 0.7 A/R, 61.5mm inducer and 81.5mm exducer.
External wastegate, think its 38mm iirc.
Intercooler is 600x300x76 iirc.
The dyno was a Mainline Dynolog Chassis dyno. Car made 300.4rwhp at 5825rpm and 275ftlb at 5631rpm.

does power drop after 5825?
my stock M52 power with an HX35 peak airflow happens around 6500rpm.
peak torque happens between 3750 to 6000/6500. ~14psi, never had it on the dyno.

[MrMuddle]

Yeah, whp drops by about 15hp and torque drops by about 40ftlb by redline which is 6500rpm.

Another thing to mention is I did pull timing below 4500rpm at WOT and taper the boost in so it only went above 10psi over 5k, to try and save my clutch. So not sure if that would affect my overall power?!

[et89]

Yeah, whp drops by about 15hp and torque drops by about 40ftlb by redline which is 6500rpm.

Another thing to mention is I did pull timing below 4500rpm at WOT and taper the boost in so it only went above 10psi over 5k, to try and save my clutch. So not sure if that would affect my overall power?!

what ECU do you use?

[someguy2800]

The eBay turbos make power just fine. Just to give you an indication on your ignition timing, you run significantly less ignition advance at 13 psi than I do at 40 psi. I think it’s time to lower the compression or build a good methanol system.

[pbonsalb]

Your chassis dyno may be conservative. I don’t know that dyno. Maybe it would be 350 rwhp on a Dynojet in SAE. Any data from people who have run on both?

Why run 13 psi low to midrange in the knock window and taper to 10 psi up top where knock is less likely? Buy a better clutch if you are doing this to save the clutch. Better to run 10 psi midrange and go up to 13 psi at high rpm.

I think anything close to 10 psi is a knock risk on pump gas. I would not try to push the limits, especially with an aluminum block since detonation could lift the head and pull studs.

A big turbo would make more power at the same boost and do so with lower IAT. But your turbo not undersized for 400 rwhp. A local person with a 0.63 turbine housing on a PT6262 or GT35R can’t remember which) on an S52 trapped 130 and was probably making 500 rwhp. Lower CR and more boost, of course, but it shows your turbo is not being pushed.

I have used water/meth for 20 years and think it’s great at reducing the likelihood of knock through octane enhancement and cooling. I like Aquamist systems.

[MrMuddle]

Thanks for the replies everyone, appreciated.

what ECU do you use?

Megasquirt 2

The eBay turbos make power just fine. Just to give you an indication on your ignition timing, you run significantly less ignition advance at 13 psi than I do at 40 psi. I think it’s time to lower the compression or build a good methanol system.

Ah ok, well that's good to know, as at least that kind of confirms where my limitations are. I think I'll look at a water/meth system then as I'm trying to avoid opening up the engine if possible. I appreciate it's also risky on the stock engine and lowering the compression with better studs would be preferable with the ally block.

Your chassis dyno may be conservative. I don’t know that dyno. Maybe it would be 350 rwhp on a Dynojet in SAE. Any data from people who have run on both?

Why run 13 psi low to midrange in the knock window and taper to 10 psi up top where knock is less likely? Buy a better clutch if you are doing this to save the clutch. Better to run 10 psi midrange and go up to 13 psi at high rpm.

I think anything close to 10 psi is a knock risk on pump gas. I would not try to push the limits, especially with an aluminum block since detonation could lift the head and pull studs.

I did a rolling road day with other cars at the same dyno and they all seemed to be lower than expected, but I was trying to avoid blaming it on the dyno, as I figured my results were still a lot lower than most others anyway.
Sorry maybe it came across wrong, I don't make 13psi until higher up the rpm range, so low to midrange is 10psi and then it ramps up over 5k to 13psi. A better clutch is on the list, still running stock clutch at the moment!


So do you guys think a poor flowing turbo manifold would make much difference to power? Or just potentially spool and back pressure? I'm thinking about re-making it anyway, but I guess the more benefits the more motivation!

Also in regards to a water/meth setup, if you're running it all the time over a set boost level etc, how often do you find you need to top up for road use and track day use? I appreciate that's a bit of a how long is a piece of string question, just thinking about if it's feasible to run it all the time for allowing me to make more on say a high boost setting.

Thanks very much.

[someguy2800]

I honestly don't think your manifold is really holding you back. Its not ideal but I really don't think it would make that much difference with tiny stock cams, stock intake, and small turbo.

[MrMuddle]

OK great, thanks very much.

Any advice on water/meth injection? What size tanks do you guys run and are the AEM v3 kits any good?

[Colby Colbs]

That is too light on timing im gonna guess. Put it on a good loaded dyno and get after it.