Quote:
Originally Posted by oldman
I would caution you on racing dynos, you can't assume what a dynojet would do.
Second, you are approaching a 10% correction factor already i.e. your car is making a whole lot less HP than this dyno shows.
Third, you are on 91 octane, I guess you can get away with this at your attitude, but it is very low. I don't know the effective dynamic compression (download cam doctor), at your altitude you could be like dunno 10.5 or something? i.e. you should have a stage 1 cam.
Fourth, AFAIK all TSP cams can take a cam phaser limiter of 20 degrees, don't know about their big stuff, you can get some of this midrange back by advancing the cam say 6 degrees till 4500 RPM, TSP should be able to give you general guidelines. IMO with fast ramp profiles, the factory phaser is not able to handle (there is dynamic walk).
Fifth, what is a catted X pipe? I also have an M6 and with factory suitcase, there are strange harmonics that lead to all kinds of issues including false knock.
Your header tube size is too small for size of cam.
I would port the heads and mill, you probably need to notch the pistons. Looking for dunno say 12.3 static. thinner head gasket too? Stock head ports flatline above .550 lift and actually flow less at higher lifts, so all that valve lift is just losing HP and torque from flow (as well as dynamic compression).
https://www.enginelabs.com/engine-te...-lt1-di-heads/
Drop the cam size to a stage 2 that works at 2000+ ft.
eliminate the cam phaser
bring tube size to 2"
ported 95mm TB or 103 TB
All of the above assuming you can get 93 octane.
On 91 and 2000 plus feet:
stage 1 cam, ported heads, maybe a slight mill to 11.75 CR.
Full disclosure I live near sea level and 93 octane my whole life. |
Hi,
I'm at 2800-3000FT elevation hence the 9%+ SAE correction factor. But SAE correction factor is fairly accurate.
Real power the car makes at those 3000FT is 455 WHP yes. Altitude sucks.
This does not change the power curve though. There are no reasons that the car should loose torque between 3300 and 4000 rpm. There is definitely and air flow issue. Power loss with altitude is pretty linear and can be simulated at sea level with partial throttle.
I have a 0 Deg lock on my cam phaser. TSP Stage 3 cam does not take partial lockout. Also there is cam phaser "float" at high rpm because of lift and duration if I were to partially lock it. Already contacted TSP about that..
I took a Catted X pipe for smell... I agree with the false knock because of harmonics though...Something I saw since I have headers. Thouse are 100 cells cats though. Pretty free flowing
I completely agree about the heads. I think most of my issue comes from that. I will give it a try after this coronavirus deal is taken care of (hopefully in a few months
)
My cam is 235/239, .645"/.635", 116 LSA 112ICL so it lifts way over 0.550....
I also agree I think I need a bigger TB. The stock ported one is probably too small.
The exhaust size not so much. 1 7/8 can be used on Z06 with much more exhaust gas flow and is perfectly fine for NA IMHO. Moreover my issue is not top power. Bigger exhaust tubes loose power down low.
As far as fuel, 91 is the best I can get, though I can get E85 in 1 or 2 gas stations.