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Yep. It has been mentioned by a few people in the know that a lot of the jap brand name valve springs do not have sufficient seat pressures when they are fitted without setting them up for intended use.

For example, a high boost/ high lift setup would need a modified seat pressure to suit, by either a correctly shimmed spring, setup to avoid coil bind.

Or a dual valve spring such as BC (brian crower) etc.

Due to Paul's fairly non standard setup, seat pressures could definately be an issue, as opposed to most people on here running bigger duration but not much lift and mild boost....

Or I could be just adding my 2cents lol...

^ lol Aggroman

He's made his mind up....that is all :)

Annnndddd 450KW :D

I asked the same thing about trigger. He said it was fine and no blips all the way past 8500RPM....

that is a very valid point - i remember once my intank pump sucked up a piece of rubber from 1 of the mounts & it sat in the inlet (had no fuel pump filter, not my doing) and symptoms were slower revs

maybe slower fuel delivery?

sounds like fuel to me Paul. Have you cleaned or replaced your in tank filter.

I had a similar problem in the gtr Marko. car would miss under load but you could feather the throttle to peak revs no problem.

The in tank filter was munted. changed it out and presto! all good.

I had the exact same problem. Under load above 4000rpm (dependant on load situation) both on road and on dyno (ramped, etc) when accelerated hard my car would have a miss and sort of hesitation. If i eased on the accelerator, the problem did not occur. We changed fuel pump, had all injectors flow tested, etc, as they are brand new, and car still hesitated (missed). I WAS running NGK platinum plugs (gapped to 0.8mm) and the car still had same symptoms (exactly like you are saying). I have super tech valves with titanium retainers, etc, 1.5mm overized valves stainless on intake and nitrite coated on exhaust. My springs are 95pounds at the seat and still car hesitating under load. Problem was found that my spark plugs were arching out under load. (Simple rule of thumb for old school mechanics - plugs up top, points down low) checked my coil packs, they were fine. Changed the plugs to v-grove and solved my issues instantly. Have also since put SplitFire coil packs and HKS plugs. I was running 12psi when this was occurring so had nothing to do with coil binding or a dud valve spring.

That's just my two cents. Hope this info helps.

If running E85 you may need to change heat range of plugs and re-gap them smaller. Give it a run on 98 and see if you have the same miss. I was having this problem on my car but only on e85. swapped to 98 and problem would dissapear. Turned out to be a cheap and easy fix after i had spent hours chasing bugs.

If running E85 you may need to change heat range of plugs and re-gap them smaller. Give it a run on 98 and see if you have the same miss. I was having this problem on my car but only on e85. swapped to 98 and problem would dissapear. Turned out to be a cheap and easy fix after i had spent hours chasing bugs.

Tried that. Nothing has changed since the night it died. Plugs the same type (just new ones gapped to the same as what they were, coils the same, fuel the same, ecu was the same.

I'll ring tomorrow and see how they went.

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