Turbo Setup question

[Proctor750]

So im getting Haltech for my fuel management for my 95 M3, and a shop nearby will fab me up a manifold. But as for the turbo, i was looking at either the Holset Hc1 or Hx35 for my car. which would suite my car better with stock Internals? and with that what kind of psi would be safe? I think compression on a 95 M3 is 10 to 1??

[Highboosting///M3]

Originally Posted by Proctor750

So im getting Haltech for my fuel management for my 95 M3, and a shop nearby will fab me up a manifold. But as for the turbo, i was looking at either the Holset Hc1 or Hx35 for my car. which would suite my car better with stock Internals? and with that what kind of psi would be safe? I think compression on a 95 M3 is 10 to 1??

10.5:1cr. And hardly anyone(especially outside of Sweden) are familiar with holset turbos. It's usually Garrett, Precision, ITS, Turbonetics... If you know what mm the compressor inducer is and what size the turbine housing is(a/r and T3 or t4) that would help.

[esirtype?]

First off, forgive me, I am not as of yet a BMW owner. I found this board while researching a BMW 325i convertible I plan on buying. I am a gear head and have been all my life. I have the intent of turboing this 325i if I buy it.

Now the reason I'm really posting here is due to the "Holset" comment. I have done a lot or research on the Hx-35 and HY-35 turbo. Try this link,
http://www.dsmtuners.com/forums/show...&page=24&pp=25
There are some generic compressor maps on the first page (if the link is still good).
Holset doesn't release their maps either.
I am running a HY-35 on my project MPI, Mitsubishi Starion (custom header, build by me and Megasquirt fuel and spark management). I really love the turbo. The G54B engines in the starquest are know for their terrible head flow with the SOHC. So I choose a hy-35 off a 2002 Dodge diesel. The turbo is a great choice for my setup. It has a small hotside and spools very fast on my unported head. Even when I ran the turbo on the TBI it spooled great for me.
Now the hx-35 has a large hot side and will max out at about 40psi, VS the hy's 30psi. However this is some serious CFM (from what I remember at 20 psi on the hy-35 was in the 750+ cfm range). I've seen the hx-35 and 40 turbo on some 2.0l eclipes engines and they are laying down 450+ whp at around 25psi.

The holset turbo is very effiencet. Like I said, I'm very happy with it. Some say it will out perform a gt-35 turbo.

Now to the BMW and holset question. The HC-1 is an older turbo, the Hx-35 would be better for you. However, I strongly recommend not using this turbo on stock internals. The reason is, these turbos are in the beginning of their effiency range at around 15psi (with 7.5:a cr). This is where I'm running it for the time being on my Starion, till I upgrade the head and head gasket. I have run it at 8 PSI, and it's no good there. From what I read, 9psi is about the safest you can go on a stock engine (s50). I am not sure on the m3 engine, but I think you're asking for trouble running a lot of boost on a stock engine, especial with 10.0:1 cr. That kind of compression is a low boost, engine. High CFM is fine however. A turbo that would probably be better suited for you would be a 20g, which have been found on Mitsubishi Fuso trucks and can be bought inexpensive at the right place. That turbo is good to about 20psi, will will do fine in the lower boost area. Another option would be some sort of t4 turbo. Something with big CFM at low boost.
I will say, my HY-35 will hit 15psi by 2700-2800 rpms, and with some headwork will be quicker. But from 0-7psi, it boosts a tad slow, past 7psi, the boost come VERy quickly!

But again, having researched these turbos, and having experience with them on another car, I don't feel this is the right turbo for a stock internal BMW, with such high compression. It's a recipe for disaster.

Let me konw if you have more questions on the turbo, I'd be happy to share with you what I know.

I personaly haven't choose a turbo yet, for this project (provided I get the car). I've seen some kits, using a t25, which is small. However, the turbo manifold only uses 3 of the 6 cylinders. I will be doing everything myself, as I always do. An intercooler will be included. As far as fuel management, I'm not sure yet, I'm still researching.

Shawn

[mattytm3]

I know some one from ICSperformance who runs 18psi on stock internals on a325 with 600whp.

[GDO]

Originally Posted by mattytm3

I know some one from ICSperformance who runs 18psi on stock internals on a325 with 600whp.

im not sure, but i think he was referring to keeping the compression ratio stock though

[mattytm3]

Well , I know of the car I dont personally know the owner. I am pretty sure he is on this forum. The car might be on their web site but any how I think all internals are stock with the great ICSperformance custom turbo fabrication thrown in there. He claims he takes it to the drag strip every weekend when weather permiting.

[Proctor750]

It turns out I got the Hx35, and have decided to lower the compression via a .140" head gasket. Autronic will be the engine management, and I have FMIC with back door setup. I still haven't had everything installed, but I think with the head gasket the compression will drop enough to use the HX35 at efficiency. Im pretty sure the HX35 and the GT35 are extremely close in comparison, and a friend of mine is running a GT35 with stock internals and thicker head gasket on his M.

[Imported Cars]

Originally Posted by mattytm3

Well , I know of the car I dont personally know the owner. I am pretty sure he is on this forum. The car might be on their web site but any how I think all internals are stock with the great ICSperformance custom turbo fabrication thrown in there. He claims he takes it to the drag strip every weekend when weather permiting.

The vehicle was built by us, the guys name is Ulysses, screen name Cardcounter. His best run on a M52 2.8 liter 328i 4 door on drag radial was a 10.7 @ 136 + mph on a stock internals with over 100k miles obn the motor low compression VIA H/Gasket. The motor bent a connecting rod @ 704rwhp, his new set-up is a fully built 2.8 and has made a hefty 996rwhp on stock camshafts to date. We did install largers cams and tried to dyno it although as soon as the turbo reaches its efficiency it destroys every clutch set-up that we have installed. Ulysses is awaiting a triple disc set-up before the vehicle get re dynoed on high boost and before it see's the track. Great things to come this year.