Hey guys. First off I want to give little bit of info about my car.

It's a 2006 Evo 9. Little under 54k miles. Full bolt ons, FP Red, Kelford 272 cams, stock springs & retainers, stock bottom end. Makes ~504/402 on a dynojet with e85 @ ~28psi.. ecu controlled boost.

So the past couple times visiting the dragstrip I noticed after winding out each gear and shifting pretty quick the car bogged really bad, at the bottom of the next gear. It would literally lose all power for a split second.. then kick back in full power(almost like spark blowout or a misfire) obviously hurting my times.

For a while i thought it might be spark blowout. But my tuner said to try shifting earlier just to see what happens. So I took the car down the track and shifted right at 7k (my tuner has redline raised close to 8k i believe). The car didn't bog! however, not winding out each gear hurt my mph and ET.

So my tuner thinks that I need to do valve springs and retainers. He thinks that could be causing the bog issue.

I am curious on the forum ninja's thoughts on the matter

 

Maybe the knock sensor is pulling timing?

 

Have you data logged your runs?

 

Whats your gap on plugs?

Also, Whats in logs for knock above 7?

Could be a WG issue, could be timing/fuel.

Need more info.

 

I wasn't able to log the runs. I guess i really need to do that to help eliminate possibilities. I may try and go back Sunday and log some for you guys.

Gap on plugs is .024

 

24 is to wide for 28 psi. Usually it needs to be 22 ~ 20. Of course this will depend on fuel too.

 

If you have a wideband output, I would log AFR's during the run to see if there is too much or too little fuel on the bottom of each shift.

-pal215

 

Okay. Going to try and log some for you guys soon.

What are yall's immediate thoughts on the stock valvetrain thought, though?

 

its not the first place i would start thats forsure. Log some runs and let us know.

 

I wouldn't think valve train would be the cause of your bogging.

Although it might not be the best idea to rev to 8k with kelfords on stock springs.

 

You haven't mentioned the fuel pump or the injector size?

No to the valve train issues.

 

Im having the exact same problem. Im making 371 on a stock block and turbo setup with a spoolinup COP and bpr8pes plugs gapped to .2 so im very curious as to what this could be

 

AEM 320lph fuel pump and 1200cc precision injectors. injectors just been cleaned & flow tested. fuel pump is brand new

hopefully i can figure it out for us