Hey guys,

I'm just wondering what the max whp should be for a GT307R.
I'm making 433 whp at 18 psi on pump gas and then 472 whp at 25 psi on C16...
40 whp gain for 7 psi seems a bit on the low side.
I'm at 3500 ft so maybe the turbo is out of breath?
Any ideas?

Setup:
83mm B18C, GE sleeved, 9.0:1, etc
BC Stage 2 NA cams, springs, retainers
Victor X
RLD Ramhorn manifold
GT3076R .82 A/R

 

Right around 500 it will start being ineficient.

 

I would say that its about out of breath... 472 @ 3000+ elevation isnt all that bad. What does the exhaust consist of? Have you made any cam adjustments??

 

Do you have any cam gears? I know with na cams you have to dial out some overlap sometimes.

 

Air at your elevation has 88% of sea level density so compressor operating at choke can only deliver 88% of its rated mass flow, about 48 lbs/min from 55 lbs/min. With this in mind, your output numbers are very good.

 

That's pretty good with what you have there... Nothing more to do. If you want more, time for something bigger.

 

I would be happy with a powerband like that!

 

3.5" downpipe and 3" exhaust. Wastegate is dumped underneath the oil pan.

I have cam gears but they are set to 0,0 right now. Any tips on where to move them?

Yeah, I actually wasn't expecting the turbo to be the bottleneck. Any suggestions for when I upgrade? GT35? PT?

 

STC Reaper

 

There is the Ball-bearing GT3584R Reaper, yes.. I don't recommend a PTE turbo at this point right now.

 

How would that compare to a regular Garrett GT35 or GTX35?

 

The reaper GT3584R and GTX3582R is like comparing apples to apples; do you like granny smith or Washington? Both make more power than a standard GT3582R but has better attributes on different areas of the powerband. GT3584R uses less rotational speed to get more torque and upper end power, while the GTX3582R uses more rotational speed and needs a bit more pressure to do the same thing.

 

OP, what fuel setup are you running?

 

Thanks shodan, that will be at the top of my list when I go turbo shopping. Does that come with a standard GT 3" 4 bolt turbine housing? What style compressor cover? Water cooled? Price?

Walbro 255, ID1000, aftermarket fuel rail, stock FPR. Ignition is stock as well.


Here's the full mod list. Feel free to make suggestions on what may need upgrading next:

Golden Eagle sleeved B18C1
CP 83mm pistons
Eagle LS rods
LS crankshaft
ACL Race bearings
Golden Eagle main studs
ARP head studs
Brian Crower stage 2 NA cams
Brian Crower springs/retainers
Skunk2 pro adjustable cam gears
Walbro 255 fuel pump
Injector dynamics 1000cc
Edelbrock fuel rail
Edelbrock Victor X intake manifold
RLD Fab exhaust manifold
Garrett GT3076R
Tial 38mm waste gate
Tial 50mm BOV
Precision 600 hp intercooler
Revhard 3.5″ downpipe
Kteller 3″ exhaust
Revhard 2.5″/3″ intercooler piping
USDM ITR transmission
Clutchmasters FX400 clutch
Gator axles
B&R breather tank
Hondata S300 with PWM boost control
Hondata 4 bar map sensor

 

Precision 6466 is a game changer. For real.

 

Maybe the fpr is setting you back, also those cams might be too big for that turbo.

 

PM'd

 

Your cam choice is absolutely terrible for a turbocharged car, so I would not be surprised if that was playing a very large factor in you losing efficiency.

 

Can't argue with that at all. Good catch

 

There are better camshaft profiles out there for turbos...@ 0/0 those cams are way too big.

 

Should I degree the cams a little bit, will that help?
Or are they completely the wrong cam to use?
Will these cams work better with a GT3584R?
Any suggestions for better cams for the current GT3076R or the GT3584R?

 

ALL MOTOR is definitely the guy to talk to about cams, but why would you ever think that NA cams would be a good profile for a turbo car? All your doing is blowing boost out the exhaust side. Obviously the advantages of DOHC is that you can degree them a little to make up for that huge flaw in your cam setup which may help some, but is it the most efficient cam to use? No way. Use a cam tailored for use with boost.

 

When I was piecing everything together I was reading the evans-tuning forums for info and these were the cams he seemed to like.

Source: http://www.evans-tuning.com/forums/v...php?f=2&t=5936

 

You can't compare that setup to yours because that setup had a bigger turbo, which is why those cams were ok. In your case, the turbo is too small for those cams.

 

Hype R cams and call it good. People make 800 on them... Why complicate **** ;O)