blown 944

To expand on my personal experiences.

I have raced subarus with gt35's and while they may have better ET's (not always) they are running slower Mph.

I've raced an e30 with a new BW turbo and have him beat in moh as well. It is a converted s50 engine using motec.

Honestly, it takes a highly modified DSM at high boost or a supra with a 67mm turbo or larger to beat my mph.

This is with me being handicapped with a crappy 2v head.

Oh and they have inconel turbine wheels...

blown 944

My research is

Compressor maps.... You can determine power capability and responsiveness
Turbine wheel flow..... Determines ultimate airflow at a given pressure ratio.
Compressor wheel design
Turbine wheel material
Back to back dyno comparisons... Do some research

In regards to short bursts on a diesel application. I wouldn't consider pulling a 40' enclosed trailer over mtn passes a "short burst"

For a couple hundred bucks, if I could make more power, yes I would swap. However, judging by the cars I race regularly they should be smoking me. But... They don't.

I think I'd go slower with a gt35 based on the cars I race.


There is no way you will win this argument with me because I am actually doing it. Not just comparing on paper.

Holset turbos are absolutely my favorite. I would not put a garret on my car again. They are too fragile.

I havnt heard of too many guys having holsets **** the bed. Garret's on the other hand... Lol... There are threads on every forum.


I don't really understand why you are so worried about it?

I also don't know what standards are necessary to prove a product.

I know that I have abused this turbo beyond what most do and it still kicks ***.

I would have blown up many Garret's by now (I have in the past) To say I'm easy on my parts is laughable.

To me it's simple. More mph, better durability, great responsiveness= great turbo.

It's really funny that this conversation is around for me. I havnt had to touch my turbo since I've switched to Holset. Whereas when I ran Garret's, I was replacing the turbo quite often.

Dougs951S

I think we can all agree to disagree, but sid pulling the mph he does at the DA he does speaks for its self. Thats real, raw 500+ wheel horse. Shredding 295 tires and boost coming on so hard as to make the car nearly undriveable also speaks for its self in the spool up/response argument. A bearing is a bearing, beefier is better. Sid thrashes his turbo and has yet to have an issue. I am not interested in the holset because it is cheap, I am interested in it because I think it is a better turbo for our cars. There are many DSM's pulling 600+ whp on the holsets with great reliability. Plus I like the idea of an oil only cooled turbo to clean things up a bit under the hood.

Dave W.

" All of this reinforcement means that there is a much heavier rotating mass, which is more difficult to spin at high RPMs, so diesel engines tend to be low RPM power plants."

LOL Yeah sure. That's why they don't spin to high rpms. LOL

blown 944

WTF is that supposed to mean? If I can make 500 hp up here then I can certainly make it at a lower elevation. Actually easier, I can turn the boost down. I have taken my car down to half of my elevation and at lower boost it ran better and I drove it home too!! 300 miles home!!

Lol, racing up here is a much more "harsh environment"


Find someone else to try to prove your theory's with. I'll keep having fun making good power with my pos Holset lol.

I was beginning to have a little respect for you, but nah.... Your just an A-hole. I'm done arguing with you. You obviously don't put 2and 2 together.

Dougs951S

I caught that too, Dave. That page was full of misinformation and flatout falsehoods.

Dave W.

I know, right? I feel sorry for anyone who uses that page as if it were an expert internet resource.

Dougs951S

I never called you stupid, or even implied that you were. I simply stated that the source you linked was full of misinformation. I could write a fairly lengthy response covering all the points that article made, but as you said, that would derail the topic. Far from an emotional response...


as you wish, here are a few links


http://forums.evolutionm.net/sale-en...0hp-turbo.html

http://www.dsmtuners.com/forums/dyno...5hp-584tq.html

40+ psi being run on a holset with huge power results. yes thats 685 at the wheels on a full HX40. try that with a garrett and see how long it will last

blown 944

Ok I'll keep playing for now.

first, The cars I mentioned are also turbocharged. You must be thinking of the LS conversation.
ie; subaru 16v, BMW 24v 3.0L, DSM 16v. All gt35 or BW s362 cars. All sub 125 mph other than higher boost DSM's and subarus.

It doesn't take a good driver to get a good MPH. I have ran the gammut in regards to god race to **** poor. The MPH is still pretty consistent.

As to why I don't go to low elevation, well now that the car is running good I don't feel as much of a need to. When I did the comparison, it was to do two things; set teh record and prove a point that DA does matter. I came right back up here and slowed down 4 mph. That was the point I was trying to prove.

I haven't said it would just "run tens" by going to a lower elevation. TBH, it would depend on how well the trans will hold up. I plan on running tens up here. I havn't published it but I have ran 11.22 @129 but couldn't back it up since traction became a big problem late in the year. I believe that scrubbing a few tenths is not going to be too hard, but who knows. Really I don't need to go much faster to be happy. Just break 130....

I do know that it is much easier to run good et and mph at a lower elevation and have proven it.

My point about racing other cars is: They are far more technically advanced, have no traction problems, are running the turbos that you mention, yet they still cannot beat my mph (which equals HP) unless they are running over 30 psi. Good driver or not they should be faster if those turbos were such a superior design. I just don't see an upside to wasting $$ on trying them.

What seems to be lost in these conversations is what the true difference is? All things equal. if you are runnign the same boost, say 21 psi, and your engine requires x amount of air to make y amount of power and all turbos fall within a good efficiency island, they will make the same power.

The difference may be response. Well that can be changed via turbine housing size, bearing design, compressor wheel design.

To be honest you have to look at the full working area of the compressor map and turbine flow. If it is acceptable for PR and airflow they all may perform very close. There may be such a miniscule difference that a change in temp may make the difference.

So then what should dictate your choice?

- reliability and durability and versatility (PR latitude)........Important to me
-100 or 200 rpms of spool time? ..... can be mainupulated,,,Marketing
-price?......... Important to me
-maintenence ability or replace...... Important to me to be able to rebuild
-brand loyalty....... means nothing without actual experience
-adaptability.......... some of these turbos are not very easy to bolt on our cars
-anti lag durability.......Important to some

I don't conform to marketing and what others may say. I try it and if I like it I use it. If it doesn't work I'll share that too.

I have had great results with what some may consider an improper turbo selection. Results though...they have to count for something. To me, they are everything.

Dave W.

If you really are here to learn, just re-write your arguments into the form of a question. Asking a question is very empowering, it opens up a dialog, stimulates a conversation and leads to a greater level of understanding.

m73m95

That's the issue. You are the one who initiates the emotional responses. Not only in this thread, but in 99% of the threads you post in. When was the last time someone, in your mind, other than yourself, had a good idea?

The problem is, I think you are fairly intelligent. I like what you did with your coilover setup. However, your lack of tact and willingness to accept other people and their ideas just overshadows what you do contribute, that at this point, I wouldn't care if you made your car fly.

You are the exact opposite of "willing to learn".

You throw out the very first link that google gives you to prove your point...and it does not contain accurate information. Which in itself is alright. There is always room to learn. However, you go about arguing with people that have far more knowledge and experience than you.

A REALLY smart guy, once told me "A man with experience is never at the mercy of a man with a theory". I'm afraid that applies here. No matter what you have read, or how many stories you have heard...Sid has the experience to prove that information wrong. He offers his own experiences for people to use. Agree with him, or not... He doesn't come to RL for a fight. He posts to help us with our own cars.

pole position

What is required to fit a Holset besides the obvious crossover/downpipe config ? Does it fit on the stock mount ?

Sorry if that has been covered before.

Btw, 11.22/129 is F'n quick at that alitude....you will be in the 10's soon.

refresh951

Rob - I definitely value your input but I think you make a lot of very definitive black and white proclamations. Why burn bridges unnecessarily? Definitely times to make a stand on principle but I say choose those times wisely and make sure you have the math and the experience to back it up. Hey I love a good theory and I have more than a few of my own. I personally think it will take both solid theory and expert experience to push the 951 platform forward. Good engineering is a lot more than theory, it involves testing to prove out the concepts. One is not more important than the other. This is an open forum and you certainly have the right to share whatever you like but just my two cents.

Dave W.

OK then let's pare down your original post to remove the antagonistic bits.


You'll have to lead the way and show us the disadvantages since Holset turbos appear to be very strong performers on the 944 and other platforms. One disadvantage I can see is the size of the hotside housing, it's big. That's why it's very common to use a smaller turbine housing when installing a Holset on a 4 banger. Easy fix.

refresh951

A vast amount of work has been done in the DSM community wrt Holset turbos. You can find a lot of answers here:

http://www.dsmtuners.com/forums/turb...urbos-faq.html