Possibility that the GXP turbo is a KKK04

[Beau]

Prior, I thought the turbo would have been the same turbo used in the saab 9-3 V6T. It looks identical, and is already dual scroll etc. But This article states it is a K04 Turbo from Borg Warner. The turbo they are going to use in VW's new 2.0T. Thier current 2.0T uses a K03S which is a K04 Compressor but with a K03 sized exhaust housing. The current 2.0TFSI makes a rather weak 200 horse.

its odd though, the K04 I didnt think was dual scroll. And GM already has an IDENTICLE turbo to the one they show, which is the that mitsubishi TD05H - 15- or 18h Variant. I can never remeber the nomenclature.

IF the GXP uses a K04 this would explain why the power drops off so hard after 5300 rpm, because the turbo is WAY too small.

expect 300 crank horse to be Upper limit of what the GXP can handle with this turbo.
Converse people :-D


http://static.flickr.com/86/225001717_e7ac70e160_o.jpg

[mena661]

Are there any other turbo's that would fit on that exhaust manifold?

EDIT: I meant from BorgWarner.

[BoostedSOL]

if it is a K04, the good news is Borg Warner/KKK is about to release the K0 series of extended tip compressors. Looking at the current K04 compressor maps from Borg warner shows 2 turbos that can run out to 260hp and run the GXP's pressure ratio before they choke.

Update the mazdaspeed 6 uses a turbo with extended tip KO internals hmmmm.

[Beau]

Hrmm, the only problem with the compressor wheel swap is. I've been told by several VEE DUB engineers that the housing itself is an issue and that a larger wheel isn't really possible.

[Beau]

Im surprised there isn't more discussion on this gang. I apologize, who was the gentlemen that had access to all of the GM papers again? I need to speak with him if possible, Chime in if you can.

Also Again the first best mod one can do for the GXP is going to be a turbo swap. Sounds crazy, but true.
The K04 is a wheezy turbo, and it seems that manufactueres LOVE to run the turbo off its compressor map. Like its designed to spin faster, just not produce more air flow... weird :]

[Red Devil]

Originally Posted by Beau Im surprised there isn't more discussion on this gang. I apologize, who was the gentlemen that had access to all of the GM papers again? I need to speak with him if possible, Chime in if you can. Also Again the first best mod one can do for the GXP is going to be a turbo swap. Sounds crazy, but true. The K04 is a wheezy turbo, and it seems that manufactueres LOVE to run the turbo off its compressor map. Like its designed to spin faster, just not produce more air flow... weird :]

Do you have its compressor map or a link to where we can see it?

I'm not too surprised that GM didn't give the GXP a larger turbo. They probably wanted very fast spool, don't all manufacturers, but not the expense of ball bearing. It also gives them the added benefit of making it more difficult for people to overboost the engine in OEM form, though surge should be an issue I'd think. Either way, if the intercooler GM provides is up to the task bolting in a larger turbo/wastegate and remapping the PCM may not be too much of a headache.

I asked this in another thread, but anybody see the challenges of the modifying the direct injection platform?

[Beau]

* Remeber These are NOT in Lbs / min. So you need to multiply 162.04, by the X axis to get lbs / min.

Then a VERY rough estimate is for every 10 Lbs/min you can expect 100 horse.

According to the gentlement that Im trying to get a hold of, he states that the stock fuel pump maybe good for 400 crank horse stock. Which the stock turbo has not a chance of scaring that flow number.

How true that number is, I do not know. It is also likley it would run out of fuel pressure very soon, although the GM SIDI motor runs at pressures like, twice that of the VW 2.0 FSI motor. Which btw will be also gettin 260 horse soon, with update going TO the K04 turbo, strengthend rods and pistons and a new pump... (Sounds like they are copying GMs design, but they wont have the piston oil galleys, nor the Dual VVT)

So there will be drawbacks. I do not feel that the electronics will be an issue... Give tuners 6 months with it, and you will probably get back tuning software.

So if we take a look at this turbo, you can see why GM decided to run 18 psi, because that puts them at about 2.2 Bar, which is exactly where the turbo can feed the most flow.

So that brings us to about .175 * 162.04 brings us ~ 28.5 LBS / Min. Well gang, that = 285 horse...
Sounds right about where an exhaust would take us. Now there probably is MORE flow to be had with Gms version of the K04, being that it will be twin scroll. So the motor will breathe better, and its possible that there were other tweaks done.

My point is, I wouldn't suspect that more than 300 horse is attainable with this turbo... (Well Beau, thats enough for me). Well its gonna have to be #1, #2, I wouldn't want my new car running at the ragged edge of the compressor map its whole life.

But also, this would again explain why the power drops off past 5300 rpm stock.

[Red Devil]

Personally, I wouldn't even use that turbo to attain the 2.2 pr. The peak efficiency is .73 and what you've calculated puts us at ~.65. It appears to be really pushed to its limits, as you mentioned. But it is one small turbo that should reach full boost very quickly.

Whether GM targeted 2.2pr, or whether the turbo selection limited them is kind of chicken or egg. But I'd guess they went from a power goal to brokering the best deal they could on a turbo that would get them ballpark.

[LatinVenom]

The name of the member you are looking to talk to is FRANKC5R.
I though the turbo was runing at 20psi and not 18psi as you have stated.
I also remember from the originals post that the fuel pump system was something like 1250lbs of presure.
My first mod besides the tires will be the exhaust system.

[Beau]

Latin, Tires and exhaust would be a pretty good addition to the car!
However, it is 18 psi according to the magazine reviews who recently tested the new GXP. Subesquently they also stated it was running the K04

[mena661]

Won't EGT's be pretty high with a turbo this small?

[Red Devil]

Originally Posted by mena661 Won't EGT's be pretty high with a turbo this small?

Well, 2.2pr, is 2.2pr, is 2.2pr in laymans terms. But the density, however, may be the deciding factor here as more power will be created by a more efficient, denser charge. The denser charge may run hotter, but how much hotter I don't think will be a factor.

[Beau]

yeah, there are several ways to increase EGTs. the best way is to have a high pressure cool charge, because the combustion is whats creating the heat.

However at times EGTs can be higher on over worked turbos as well. But I think the first is in check.

My point about this is, I think with a turbo swap like a new GT-K Turbonetics Twin scroll will literally be right up this badboys alley with a ball bearing unit. It'll probably similar in spool, and free up more than enough horse top end.

[mnavarro]

Originally Posted by Beau yeah, there are several ways to increase EGTs. the best way is to have a high pressure cool charge, because the combustion is whats creating the heat. However at times EGTs can be higher on over worked turbos as well. But I think the first is in check. My point about this is, I think with a turbo swap like a new GT-K Turbonetics Twin scroll will literally be right up this badboys alley with a ball bearing unit. It'll probably similar in spool, and free up more than enough horse top end.

you guys also forget that DI helps cool the intake charge. This should also help mitigate high egt.

[Beau]

I didn't forget, I just wasn't going to get into that with the guy a couple of posts above. I was trying to stay on turbo size topic :}