refresh951

Sounds good, my personal opinion is I would run about 8:1 CR (or even a little lower). The stroke makes the car very fun down low and you will avoid HG issues. This has been discussed quite a bit so no need to re-hash but just my opinion. Good article on the subject:

http://www.modularfords.com/threads/...boost-pressure

Dougs951S

Hmm, the build isnt going to happen overnight so I have some time to look for a 3 liter crank. I just have access to a messed up N/A block with the crank ( bores are out of round ) so I figured that would be a good basis to start on. If I decide to go the 2.80 route, I think I'll go with -20cc wiseco pistons; combined with the slightly reduced stroke it will let me get a reasonable bump in compression without getting into dangerous area. Final static should be ~8.4:1.

refresh951

Spent the last few days getting the tune on the car worked out. I feel really good about it. Rogue's Tuner/Logger has been an awesome tool in this process! I am running an MBC with stiff springs in the WG (1.1 bar) and have great boost control. The car feels great even with pulling 3 degrees of cam timing. Ready to hit the dyno tomorrow night. The plan is to get a 15 psi run, then a 18 psi run, and then if everything looks really good a 21 psi pull. The most important thing I am looking for is some complete baseline runs even if only at lower boost.

Josh B

Looking forward to it

333pg333

Less than 8:1 for 400whp Shawn?

refresh951

Yes, I was running 8:1 CR on the 2.85L and hit 410 rwhp with the TO4E (#8 hotside). That was with boost falling off to 17 psi at 6K rpm.

blown 944

No news??

carlege

there were improvements

but i believe shawn is going to go by himself next week and see what he can do with some tweaks.

refresh951

Ended up talking to a Aerospace Engineer with a PHD from Georgia Tech until really late after the dyno. Great discussion but dyno was once again challenging. I got a couple baseline runs that appear to be at about 12.5 and 14.5 psi. Early next week I am going to go back to the dyno for a two hour session. I will post the curve for these runs tonight as I had to leave early this morning for work. Definitely flattened out the torque curve up top.

blown 944

Glad to hear that you took the conservative route. Also glad you're doing a dedicated session.

At those boost levels, the tq curve should be pretty flat. You're not really pushing through your restrictions and VE limits.

Still curious about the low end change from cam timing and the overall power level at 14psi.

refresh951

Been to the dyno a couple times in the last week working on the tuning. I now have boost under control and the motor has been solid with no real issues. Been looking at cam timing and ignition timing. I am getting closer but have a bit to go. Still not where I want to be on the top end. I will be focusing on the TB, the intake, and couple different cam grinds. Once I get the curve sorted I will be making much higher psi runs (20-24 psi). Thought I would post this dyno comparison between my 2.85L and the 3.12L, both runs at about 1 bar. This motor makes awesome bottom end and mid range torque! My main focus is to improve as much as possible the top end VE. I am suspecting the right cam is going to get me a long ways towards my goal.

333pg333

Great improvement in numbers. The curves will improve. Very healthy TQ at just 1 bar!!!

Paulyy

Nice run shawn. once you flattern that curve and bring that top end up. at 15 psi you should see 450 rwhp. or more

Thom

Interesting results, congrats.
Just goes on to show how long runners can't be beaten for mid range thrust!

By upgrading the cam without touching the intake it's possible that you will be adding mechanical stress at the top end to the point it may not yield worthwhile results given that a 3.xL engine moves quite a bit more air than a 2.5L.

I run the same 9R cam and the butt dyno suggests I've got a torque plateau from 4k to 7k, with a short runner intake. The car feels slower than with the stock intake because of less low and mid range thrust but acceleration times have shown the opposite to be true. This suggests to me my engine may be running quite efficiently. FWIW anyway.

Now that you have found a satisfying tune with the current engine components it would be interesting to note acceleration times from 60 to 100mph (in 3rd gear) between each time you replace components.

refresh951

Thanks Patrick!

The trick will be coming up with a solution the improves the top end without too much compromise at low and mid range.

And 94.75 mm stroke!

No satisfaction yet.