For those that are curious about my recent 467 HP run and my boost reponse:

I was paying attention on the drive home and did several "pulls"
I'm only running 16psi right now but:

In 5th gear I started at 2500 RPM and floored it. I saw .6bar by 2900 the W/G started to crack at 3200 and by 3500 I was at 16psi, full W/G... so I definately believe that steve was seeing 19psi at 3900.

I think the current setup will break 500RWHP with another fuel pump.


and I wasn't even running the water injection installed on the car.

 

Try the same thing in 2nd or 3rd gear. See if it changes.

 

Can you post your setup as well?

 

OK, I'll try second and third.

I have a heavy street port with all the goodies and an E6K. The turbo is close to a BB PT67 with a divided turbine housing and a .84 A/R 4" DP into an Amemiya dual 3" rear section. The manifold is a custom divided stainless with dual TiAl 38mm gates that I designed.

-Chris

 

Good luck doing that... With 460rwhp he'd be lucky to watch the boost gauge and tach without hitting the ditch I suppose that's what dataloging is for

 

I just wanted to see the difference. I wasn't trying to make him wreck

 

LOL. I suppose a data log is the best way to go

Geeze, I just filled up Monday night and I"m down to less than a quarter tank already hehe, this is gonna be expensive

 

It's a small price to pay to feel boost like that
What is your tune for cruise situations? Mine is about 14:1 and I'm getting 15-18mpg with "sprinted" driving on occasion.

 

I dunno, I'm gonna look at it over the long weekend comming up. 15-18 doesn't seem too bad, I'm pretty sure I'm less than that now though...

 

hmm, I might have to get a t66bb now...

 

Hey chris how fast were you going when you did the 5th gear pull? Did you even look down?

Matt

 

Ihor, where's that coming from? I thought carx7 was running a gt35/40....?

not that that's a bad compressor choice....

 

Hehe, my speedo isn't connected right now... so I have no idea how fast I was going. I can say that 4th gear pulls really hard at 5-6k RPM... and I'm pretty sure that is going really fast

As for my turbo, I'm actually running a custom spec Garrett turbo... which is very similiar to a BB PT67.... 66.7mm GT series compressor wheel with a GTQ turbine wheel. I didn't like the undivided T3 footprint on teh 35/40.... now the new 40R...hmm.....

 

why did you go small on the turbine housing with a .84 a/r and then use a big 4" downpipe??

 

All part of a theory that I was running off of with my turbo design.

The short version is reduced back pressure for the turbo to decrease spool with a 4" exhaust... The .84 was also partially chosen to help spool.

 

Ya, it will help spool using that smaller turbine sizing, but a 4" downpipe seems like overkill matched up with that housing. That's what I was getting at.

I thought with a good sized port you'd choke up the motor on the top end with that turbine housing size even if you have a pretty good sized turbine wheel. I guess that was sacrificed for spool time? What size turbine wheel are you running?...I don't understand GTQ wheel?

I think I'll have to go try this.... 5th gear @ 2500 and then WOT right? I have a 1.15 P trim on a plain jane HKS cast manifold.

 

I may have sacrificed some top end with a .84... but then again I made almost 470 and we only stopped because my fuel pump was running out of steam, that and we were only use roughly a 96octane gas. Plus, the turbine housing is only a restriction if the exhaust gasses don't have somewhere else to go *before* they get to the turbine housing

Everyone else I've seen making this power is on full race gas 101, 108 or even C16 so I'm not to worried about this being restrictive.

The GTQ is Garrett's latest turbine wheel and is part of the GT series of wheels, newer design, more efficient etc. From all that I was told it is supposed to flow like a Q, spool like a P. It seems to work well. Same goes for my compressor wheel... GT series.

Try the 5th gear thing, I'd like to see how it works on someone else's system just for comparative purposes. Also, what sort of power/boost are you making/running.

 

Well, I tried doing this tonight, but my car didn't want to cooperate I had an intercooler coupler pop off in the middle of nowhere and didn't bring the tools with me. I'll try again tomorrow night. Got in a couple mediocre 12.5 psi (WG spring) runs.

Looks like 5 psi around 2700-2800, WG cracking at 3500, 12.5 psi by 4000.

I should note that I feel like my car has slower response since I first used this setup a year ago. It made great power, but since then I have been battling small gremlins.

T61, 1.15 turbine a/r and I THINK P trim wheel
HKS Cast manifold
HKS Race WG
POS crush bent and dented to fit WG 3" downpipe.....soon to be replaced.

I'll try again tomorrow night....maybe that coupler was leaking a little during these runs before popping loose at 15 psi. I've been suspect of a boost leak somewhere for a while. Obviously I don't get to drive the car all that much.

BUMP for all of you others to go try it....

5th gear, 2500 rpm, WOT