S38 turbo project?

[ISO_524td]

I've wanted to buy another 524td and use for a back-burner car project in making a killer gasoline turbocharged car. It's my way around the CA smog laws. I was considering an NA M30 or 745 engine swap as the basis for the project.

However, I'm selling my E36 M3 and an interested party has a wrecked E28 M5 that he could use as a partial trade for my car. He has let me know there is at least one person here that has turbocharged the S38 engine.

So, how hard would it be to do this? Do the M30 turbo exhaust manifolds bolt up? Is the cam timing or compression ratio too aggressive for turbocharging?

Thanks for the help!
Chris H.

[turbodan]

The m30 manifolds dont bolt up. The s38 bolt pattern is more like the m50. So you need an s38 specific manifold. It looks like a guy could cut up the stock tubular manifold to make a turbo manifold, but I've never seen that done. The CR is awfully high for FI. Dinan swapped out the engine block, presumably with the low compression m88/3 block from BMW, for thier turbo cars. I imagine you would have to as well. The stock cams would make for a wicked powerband. They were only 248's, so they would probably work pretty well. I think Dinan retained them on thier turbo s38, but I'm not sure. They are designed for emissions regs and a catalyst, so they cant have too much overlap. And its not like you cant retard or advance the intake or exhaust cams to suit your needs anyway.

[Ken H.]

Read "Lucifer's Hammer", Parts 1-12 on this forum. Think. Hard. Twice.

[M635CSi]

So, how hard would it be to do this?

Not hard, expensive...

Do the M30 turbo exhaust manifolds bolt up?

Negatory.

Is the cam timing or compression ratio too aggressive for turbocharging?

No.

The stock M88/S38 piston design is not for a turbocharged engine. You may want to specify a lower compression ratio if you buy new pistions.

[Rich Euro M5]

Dinan swapped out the engine block, presumably with the low compression m88/3 block from BMW, for thier turbo cars.

You need to get your facts correct before you post. The Euro M88/3 engine has more compression than the US/NA S38B35 (10.5:1 vs 9.8:1). If Dinan did anything they had custom forged pistons to lower the compression ratio from 9.8:1 to something more suitable for FI.

Rich

[Ken H.]

Rich has it right. Dinan used bone stock US spec M30 and S38 motors for the turbo platforms.

What was done to the motors was as follows:

1. Moving components blueprinted and balanced.
2. Forged pistons (7.8 to 1).
3. Stock con rods replaced with Crower forgings.
4. Head cut for an O-ring.
5. Copper head gasket.
6. Head bolts replaced with studs.
7. Larger injectors used (don't recall the # rating).

Beyond the foregoing, there were no other internal engine modifications.
The Motronic was upgraded with a Dinan chip burned for the turbo application, and augmented with a Turbotronics piggyback controller.

8. The only drivetrain modification was the use of a CenterForce clutch.

My source on all this is from Declan Doyle and Jeff Hecox, now in senior management at Dinan Corporate. I have known these gentlemen for nearly 18 years. Both of them were intimately involved with the E28 5-series turbo project from it's inception.

HTH

[ISO_524td]

Thanks again for the feedback. Maybe I'll reincarnate the wrecked M5 in its existing NA form instead with some xtra stuff to bring it over 300hp? I really wanted a turbo though as it's a blast to do all of the kills like Duke535 is doing.

So M635C Si, you mentioned it was expensive. Is this just for the custom exhaust manifold fab or what other expenses? HD clutch and turbo pistons would be a good idea and I glad to see the camshaft could work. Figure the turbo to be in the $1-2K range. Are there any funky electronic controls needed or a special chip?

BTW - my goal would be much simpler than the Lucifer project in only pushing a moderate boost level to keep costs and reliability within reason.

Sorry for all of the questions!
Chris H.

[M635CSi]

So M635C Si, you mentioned it was expensive. Is this just for the custom exhaust manifold fab or what other expenses?

The exhaust manifold/header is a minor expense for this project. The turbo exhaust header/manifold is available from a number of sources for a reasonable price.

HD clutch and turbo pistons would be a good idea and I glad to see the camshaft could work. Figure the turbo to be in the $1-2K range. Are there any funky electronic controls needed or a special chip?

Installing a heavy duty clutch disc and pressure plate is a given. Turbo pistons are different in design than NA pistons. If you want a reliable engine, install pistons designed for forced induction. The funky electronics are the fun part and really where things start to happen. Get the electronics right and your engine has a chance. Get the electronics wrong and your car will end up parked for long periods of time between replacing melted pistons and blown head gaskets.

All in all, I wouldn't advise this project to anyone who hasn't had many years of automotive experience and some pretty deep pockets. Of one thing I am sure, you don't know what you're getting yourself into.

BTW - my goal would be much simpler than the Lucifer project in only pushing a moderate boost level to keep costs and reliability within reason.

You pays your money and you makes your choice but when everything is said and done, there is a baseline you can not go below and still have a reliable engine.

[turbodan]

Regarding the block, I was referring to the part for the low compression version of the m88/3. That would be a different block than the standard m88/3 and s38. P/N 11-11-1-310-098 is the block I am referring to. See http://www.bmw-m.net/techdata/dinanturbo.htm. When they say "low compression block" I take that to mean that it is not the standard s38 engine block. I didn't say they definitely used the low comp m88 block, but I dont know that they didnt either. I can't see Dinan sticking a fat head gasket in thier turbo M6. I was merely suggesting the possibility that they could have used the low compression block already available from BMW. I guess the information from Mr. Doyle at Dinan clears that up.

[M635CSi]

Regarding the block, I was referring to the part for the low compression version of the m88/3. That would be a different block than the standard m88/3 and s38. P/N 11-11-1-310-098 is the block I am referring to. See http://www.bmw-m.net/techdata/dinanturbo.htm. When they say "low compression block" I take that to mean that it is not the standard s38 engine block.

That's Dinan marketing. I recently bought an engine out of a Dinan turbo M635CSi and the lower compression ratio was achieved though aftermarket low(er) compression pistons. Dinan used the engine block they lifted out of the car when they turbo charged the M88/S38 engine.

I didn't say they definitely used the low comp m88 block, but I dont know that they didnt either.

There does not nor did there exist a BMW "low comp m88 block".

I can't see Dinan sticking a fat head gasket in thier turbo M6. I was merely suggesting the possibility that they could have used the low compression block already available from BMW. I guess the information from Mr. Doyle at Dinan clears that up.

Dinan couldn't lower the compression ratio through the use of a taller (lower compression) block because BMW does/did not sell a taller block. BMW (and Dinan) lowered the compression ratio by using pistons with a reduced compression height.

[Ricky535]

Go to KB Motorsport in Vista. There's an m5 with forced induction.

[Justin_FL]

The exhaust manifold/header is a minor expense for this project. The turbo exhaust header/manifold is available from a number of sources for a reasonable price.

"Who" might that be?

[M635CSi]

The exhaust manifold/header is a minor expense for this project. The turbo exhaust header/manifold is available from a number of sources for a reasonable price.

"Who" might that be?

A friend is having a tubular top mounted turbo manifold made up for his E28 M5. I've been thinking of asking him to have one made for me but I already have a Dinan exhaust manifold. I figured if they're going to make one, might as well make a two...