200whp with stock N/A rotating assy?

[digger]

that will have zero effect on cracking under the cam bearings.

i run a colder t-stat as aluminum doesn't like heat and fatigue loads so i'm hoping this provides some benefit as my temps are normally at the 11'oclock tick except hot days with AC in traffic , i wonder what coolant pressures are in the head. BMW did raise the cap bleed off pressure at some point but that may not affect the actual operating pressures in normal circumstances.

the most likely thing is differential thermal exapansion or some manufacture casting, cooling and heat treating process that causes poor microstructure

[bmwmaster81]

Omg, bad luck.
This happened also to my old engine the head cracked at the same place.
Then i rebuilt it and the head gasket blew out on 5th zylinder.






Now with my new build i try to reinforce the head as much as possible.




With Arp bolts and O-ringing an plates like the turbo guys do.........i hope it will help. Becase when the head will be fu...... up the next time, this will be the finish with m20 in my car and i sadly switch to another engine.

Maybe we should put all information together to research why it cracks and look out for possibilities to solve this problem......

[ForcedFirebird]

Head is off, new core is being prepped/ported/machined. Owner was a bit bummed, but happy it was noticed now, and not after the coolant wiped out his new engine.

Worst part is, the old head was pressure tested and ran for a year before it cracked. Never overheated, but was abused.

[ForcedFirebird]

i found there was about 10-15ft-ftlb loss in midrange at 4000-5600rpm with 2" shorter runners but only 1hp more

Pretty consistent with here. Duty cycle is close to yours, too. These Ford 24lb injectors are the single pintle and shoot pretty sharp.

[digger]

shit!!! mayo

[ForcedFirebird]

:(

[digger]

Had some fun today at the dyno. Made a best peak hp @ 217, but that was with the runners shortened and mid range TQ suffered. Overall best "power under the curve" was a peak of 214hp/202tq.

Sorting the graphs, will post some up.

i found there was about 10-15ft-ftlb loss in midrange at 4000-5600rpm with 2" shorter runners but only 1hp more

[ForcedFirebird]

Ugh. First I grabbed the wrong folder from the dyno PC, so can't post any graphs right now, but that's not the worst part.

The vapor in the video turned out to be a developing problem. Got worse today, so opened up the valve cover when we got her back in the shop. Lots of milkshake on the back of it, but dip stick looks clean - threw the pressure tester on it and that stupid #6 cam journal cracked :(

[tinkerputzer]

Nice work John :up: Man would i love to run some of those RHD itb's on my 3.1 with a better cam.

[ForcedFirebird]

Had some fun today at the dyno. Made a best peak hp @ 217, but that was with the runners shortened and mid range TQ suffered. Overall best "power under the curve" was a peak of 214hp/202tq.

Sorting the graphs, will post some up.

[whitebulat22]

Wow, my 2.7i is fun, but i can't believe how much this setup stepped up from oem and can't wait to see what the new tune does!

[LJ851]

Cant wait to see the results!!

[ForcedFirebird]

Yeah. Just tough to get in high gears with a loud race car and industrial/public streets. If they are too small, will order, but the customer is getting antsy about having his car back. Did some rough calcs based on old vs new flow etc, should be in the 80's duty as you suggested. Time will tell though, eh?

[digger]

Put 24lb in tonight and preliminary tuned it, will dyno tune tomorrow.

AFR's on the WB look ok?

[ForcedFirebird]

Put 24lb in tonight and preliminary tuned it, will dyno tune tomorrow.