Valve Spring Install Question

[ph363]

Also, are you having high RPM break up and if so, at what psi level does it occur?

Reviving the dead here.... I am at the same crossroads as the thread op, but I am seeing high rpm break up. Happens at 9.8psi and above, feels just like failing coil packs at 6k and above. I am guessing spark blowout, but I am curious about what you have seen.

Valve Spring Install Question

So after installing my twin turbos and going through tuning with Lund he said to replace my valve springs to correct exhaust timing being thrown off at higher rpm. So I got a set of PAC 1234X springs and the ST-105 tool to replace them . I did my oil pump gear install when I bought the car...

www.svtperformance.com

 

[gimmie11s]

Reviving the dead here.... I am at the same crossroads as the thread op, but I am seeing high rpm break up. Happens at 9.8psi and above, feels just like failing coil packs at 6k and above. I am guessing spark blowout, but I am curious about what you have seen.

What vehicle, what set up, what spark plugs, who is tuner?

 

[ph363]

What vehicle, what set up, what spark plugs, who is tuner?

Gen2, hellion top mount, e85, 6510's @ 0.040, lund on pcmtec.

Have fresh 6510s at 0.025 going in tonight.

 

[Bullitt1448]

Gen2, hellion top mount, e85, 6510's @ 0.040, lund on pcmtec.

Have fresh 6510s at 0.025 going in tonight.

It does sound like plus to me, possibly a coil going south

 

[gimmie11s]

Gen2, hellion top mount, e85, 6510's @ 0.040, lund on pcmtec.

Have fresh 6510s at 0.025 going in tonight.

Youre on the right track.

You are experiencing exhaust pressure valve float. Make sure your exhaust is free flowing... running turbos through factory mufflers is a bad idea. Must have 3" after the turbos into a straight through muffler at minimum,

Also... .040 plug gap is way too high. You can bring them down as low as 015 or so. I would also say .025 is too much. Start at .020 and go down from there.

6510's work well... probably too hot for high boost in the summer, but Ive had luck with 6510's. Low boost (under 15 psi) they will be fine.

 

[ph363]

Youre on the right track.

You are experiencing exhaust pressure valve float. Make sure your exhaust is free flowing... running turbos through factory mufflers is a bad idea. Must have 3" after the turbos into a straight through muffler at minimum,

Also... .040 plug gap is way too high. You can bring them down as low as 015 or so. I would also say .025 is too much. Start at .020 and go down from there.

6510's work well... probably too hot for high boost in the summer, but Ive had luck with 6510's. Low boost (under 15 psi) they will be fine.

Thanks for the replies guys. Plugs took care of it - car pulled clean and hard through 12.8psi. I will wait to push it any further until it's on a dyno.

I had the plugs in before I saw this, so they are at 0.025. Will close the gap a bit more.

Float will deffinately be an issue with this kit. I am running catless with 3" s-type, but the single down pipe is a killer.