1G-350Z

I think everyone here understands that there are a lot of factors other than the turbos CFM...

I think the jist of this whole thread is that based on compressor maps neither a Garrett GT25R or a GT28R can support APS's 800hp claim...


Some one please prove me wrong....

When I was in the market last summer for an APS kit Peter PM'd me saying that they were GT2835R (which whould support their claim).

I was @ the Garrett booth @ SEMA AC and the 2835 was a huge turbo, in comparisson to a 25 or a 28...

As Mike from VRT might know, the exhaust manifold is a similar set up as the APS... The turbos mount right up by the heads, absoultly no room for a big turbo, unlike the Greddy where the exhaust manifold drops the turbos allowing more room for the big 18g's with external wastegates...

Wright Sharif

atlsupdawg#2

How much smaller are the gt28r's compared to a t3/t04e??

1G-350Z

Not sure... I think roughly the same size.... Not sure though...

MIAPLAYA

iTrader: (3)

gt28rs are a bit smaller then a T3/T4...probably more comparable size wise to a straight T3. But this all depends on what compressor housing is used, etc..

BriGuyMax

iTrader: (4)

APS Lists their turbos as GT2871R for the Twin Turbo kit.

Here's a link to pictures and specs of said turbo:
http://www.nzperformance.co.nz/store...ett%20GT2871RS
That turbo in the picture looks nearly IDENTICAL to the APS turbos that I have bolted to my car. The only difference I can see is the inlet diameter on the compressor side is slightly larger than my turbos but the wheel itself (the important part flow wise) looks identical.

As you can clearly read in the specs on that link a single GT2871R is rated @ 400hp. Two of them and viola...800hp.

Sharif@Forged

iTrader: (92)

I knew there was a perfectly good explaination for this.

1G-350Z

Ok that makes sense, so your turbo looks nothing like this...



That's from the APS web site.....

Your turbos look like this...



These are pics from a APS TT install from this board....



Hmmmmmmm I guess photographs tell a different story....

"Viola I guess we are all still very confussed..."

BriGuyMax

iTrader: (4)

My turbos look exactly like the ones in the first image and last image. My turbos are also very similiar albeit slightly different externally.

Here's a good pic of my exhaust side.


I think you are taking the overall "look" of the turbo too literally. The compressor side outlets and inlets are slightly different (ie. bolt instead of clamp), and the orientation of the exhaust and compressor housings are specific to the application. So the turbos externally will look a little different. Look at the compressor and exhaust wheels.. They are what really tell the story and those look nearly identical. The APS turbos compressor wheel may actually even be a little bigger than what the turbo I linked to has.

I think the problem we have here is people don't understand that you can shove many different sizes of wheels inside the same size housing, meaning that the external look of the turbo can't tell you how much power you can make with it.

1G-350Z

I understand you can have differnent size wheels in different size compressors.... On the compressor side they may have a 35or71 wheel in a 25 or 28 housing.... Untill someone opens these two turbos up and compares them side buy side... Based on the images we have There is uncertainty.... Or if we see 700whp on stock APS/Garrett TT's

I have to admit APS is a pretty tight company, when it comes to R&D and overall engineering.... It's hard to imagine that they would make hudge claims and not back them up.... But seeing is believing, and for certain time will tell

barthelb

I guess your not the only one with this theory. So what if the Aps turbos that come with the kit can't make 700whp like they claim. False advertisement?

1G-350Z

They just loose alot of credibility...

BriGuyMax

iTrader: (4)

I don't see them claiming 700whp anywhere. I did see 800 CRANK HP claimed..which could be anywhere from 650-720whp depending on correction factor.

Frankly I don't think the 700 or 800 or whatever number should even matter to people purchasing this kit. If you bought an APS kit because of "800hp potential" you should be kicked in the nuts. There's a lot more that goes into building an 800hp car than simply turbos, piping and a piggyback. The fact is these turbos are VERY well matched to this motor for pretty much any streetable power level that people have run up to 550whp so far. I'm very happy with that considering S/C guys have to change out their blowers just to break 450whp.

Sharif@Forged

iTrader: (92)

They dont claim the engines will produce 800 crank HP. They only claim the turbocharger will flow enough mass air to produce 800 crank HP. If you take a conservative 15% drivetrain loss, you come to 680whp. When an engine is confronted with x lb/min worth of air, it can make a wide range of power...from very low...to extremely high. Things like heads, valves, cams, plenums, exhuast back pressure, type of fuel used, AF ratio, timing profile...etc...can make an enormous difference in power. In my eyes, I think APS is off the hook on this one, as several people are 600whp+ with the APS TT kit.

Here is another example: At 16.5psi of boost on my personal Greddy kit, we have peaked 622whp. Others have required 20spi to achieve the same power. Why?? Becuase they have different heads, cams, tuning strategies, etc..

Sharif@Forged

iTrader: (92)

Here is a reply from Peter he sent me on the "other" board. FYI, the reason he doesnt post or respond on this thread is because he is banned. I suspect if you PM him on "tech", then you will get a rapid reply.

From Peter:

Hi Sharif, A happy and safe new year to you my friend, I hope all is going well for you. I just read that thread quickly and I think that your input is very accurate and factual, it takes a lot more than just big turbochargers and intercooler system to generate very high horsepower given the flow limitations of the entire engine and exhaust system.

Our head techs and engineers have conducted a significant amount Research and Development on the VQ TT engine over the last 6 months (products of this research to be released in 06 if all goes to plan). There's defintely major flow restrictions via the cyl head, inlet manifold and cam timing at approx 600 genuine rwhp (power figues at the wheels vary dramatically on different dynos as I'm sure you know). These issues need to be thoroughly addressed to break through the 700 whp barrier no matter how large the mass air flow is of a given turbocharger.

I think the point that some guys miss is the fact that most turbo system manufacturers size the turbochargers to produce the intended horsepower level at relatively low pressure ratios/boost pressure (around 8 psi) in order to keep the cylinder pressure to a bare minimum for a high compression NA engine.

If there's any other info or feedback that you like feel welcome to send me a pm and I will provide you with the answers to your questions.

Best Regards,

Peter

mraturbo

iTrader: (1)

Thanks Sharif for the clarification. Your posts are always factual and interesting.

Warmly

Michael

drewby

hi sharif, whot cams would you run with around 14 psi, & Forged Internals, & whot cams do you run on 16.5 psi motor, thanks, D

Sharif@Forged

iTrader: (92)

JWT S1 cams for now.

drewby

hi again, thanks for the chat & the offer, . i forgot to ask for a price on the cams. cheers. D