Hoffbro's Scheisse-rot Turbo

[Hoffbrohaus]

Finally got some time to bolt it back together and run it. But sadly no luck, in fact it may be worse It's inconsistent and once after a decent 3rd gear pull 4th gear didn't build much at all, so that was weird. I may have introduced a new exhaust/pre-turbo leak with the grinding. I will check when the car cools and I can take the downpipe off to run the smoke tester.

I did 3 runs and got some different numbers but still all close to what I had before

RPM	Run 1 PSI	Run 2 PSI	Run 3 PSI
2500	1.3	1.9	2.1
2700	2.3	2.7	3.2
3000	2.3	2.7	3.2
3200	3.2	3.5	4.6
3500	4.9	5.2	7.3
3700	6.4	6.9	10.1
4000	10.5	10	15
4200	13.3	14.8

So I think I should start saving for a new turbo. Also, wondering what you guys are running for gaskets. Maybe the grinding didn't introduce an exhaust leak since I noticed the turbine inlet gasket from RSI was starting to separate. Maybe that's not sealing well now, it's the MLS style, thinking I should get one of those metal plate gaskets. Also for the RSI manifold I'm using the single piece MLS gasket they provided. Are you guys running stock manifold gaskets without the heat shields? I saw these on 7speedshop.com BMW M20 HD exhaust manifold gasket set Turbo – sevenspeedshop (7speedshop.com) My concern is the thickness making it hard to bolt the RSI manifold on.

[Panici]

Plenty of meat left on the sealing surface, possible bad gasket like you said.

After everything you've tried, I'd suspect the turbo as well.
Always gambling with a used unit, maybe it was run dry, or run really hot, and the bearings are damaged.
Or heck who knows, maybe the compressor/turbine wheels are mismatched to the housings and the clearances aren't what they should be?

[Northern]

I'd try to check clearance between turbine/housing and compressor/housing like Varg and Panici said. I'd try with a cheap set of feeler gauges, hopefully you can find some sort of spec for your turbo. Also try to get a feel for how it spins by hand, maybe fire up a video?

Are you sure the wastegate isn't having an issue, sticking open, hoses wrong, hose kinked, or something? check routing vs usual Tial MVR info.

Any chance that the exhaust is restricting a lot?
You'd probably have a lot of heat and feel like something is wrong outside of boost not hitting target, but try to sneak a look at the flex joint and any glasspacks to make sure they haven't collapsed.


For gaskets on my 24v I run the OE style manifold gaskets and one of those T3 stainless MLS single sheet gaskets that look like this. I've reused it twice with copper spray and it still seems to seal.

https://www.amazon.ca/Turbo-Gaskets-Inlet-Stainless-Garrett/dp/B08CVPFTHK

[parkerbink]

Looks great! I have been going to Xact since 2008!

My SC Sequoia with a slipping belt and needing a better tune Dynoed At 574/537 there!

[Hoffbrohaus]

Put a new exhaust manifold gasket on since the MLS one was splitting. No difference, still massive lag.


So I took the exhaust off completely and ran straight out of the downpipe. No exhaust restriction. Also took off the intake filter and pipe in case the silicone was collapsing or something. Same massive lag.

And of course previously smoke and pressure tested intercooler piping with no leaks. Verified impeller and housing sizes with varg, turbo also spins freely by hand, not fast tho.

Since it is a used turbo I just can't find any reason not to buy a new one. We've tried everything else.

[AWDBOB]

Sucks you weren't able to resolve the lag. The new g25/g30 pulsar copies are pretty dang good for the price. I drove jakeb's car with a pulsar g30-660 and a kangaroo manifold and it lit up instantly. May be something to consider so you can get a modern turbo on the car without breaking the bank

[zwill23]

Tough break, but I think you're going about diagnosing the right way. Never experienced a pulsar turbo, but I'll throw a BW S257 SXE w/.82 rear housing in the mix. Good reliable turbo sized well for an M20, in my personal experience at least.

[varg]

I've heard good things about the Pulsar turbos, if I were to replace my E30's ancient T3/T4 now I'd be very tempted to get one of the pulsar G30 knockoffs because they are supposedly very responsive and make good power from a small package. I have a BW in my wagon, I chose that because I know they're pretty cheap and durable so good for a daily driver. Good power but not a small package.

[Northern]

I like my S257 as well, but on an M20 I'd drop to an S252 if I went BW because I think it'll still do about 450whp.

That said, everyone is ranting about Pulsar stuff, so at this point I'd give that a shot.

[AWDBOB]

My buddy just got his turbo car tuned last week with Jake’s kit that uses a pulsar g30-660 with the kangaroo mani and the results were quite impressive.

I’ll see if I can get him to share it here.

Edit: here ya go

eight~deuce's car. Jakes turbo kit and ECU. Flex fuel setup that adjusts tune based on what's in the tank. Stock M20b25 with head studs and a fresh head.

Pump graph: 14psi
Ethanol graph: 18-19psi

Screen Shot 2024-07-13 at 9.23.49 PM by Bobbie Morrone, on Flickr

[varg]

Did you ever get this car sorted out?

[Hoffbrohaus]

Did you ever get this car sorted out?

Nope (sorry replying 5 months later). I have been away from the forum for a while working and tinkering on the car. Long story short, I gave up. I bought a brand new T304E but 50 trim thinking it was my used turbo and a 50 trim should be even more responsive. No change at all. Still not hitting peak boost until 4200 and barely making anything at 3500.

After spending the money on a new turbo, smoke testing everything, putting on a new manifold gasket, blocking off the wastegate, pressure testing the IC piping, comparing my ignition and fuel tables to yours, I just got too frustrated. So I am in the midst of pulling it all off and going back to "stock" (keeping wasted spark, e36 tps, gm iat etc)

I have almost convinced myself of trying a log manifold with in internally gated turbo off a 2L chevy just to get a little extra power :) but we'll see, maybe when i'm back to stock i'll discover what the problem was all along.