for the past year every pass i made i was trapping in the 120's. my last 4 runs i trapped 124 ,119,117,114 mph. the only thing i changed since the last 124mph was the tranny. i do have smoke at start up and when the car is cold. could i have blown my turbo?also my boost in about 1psi under normal?. what could cause my car to lose 10mph since 5/13 to 6/3? thanks in advance

 

Trap speed = power, so you are losing power somewhere. Does the motor seem healthy? Check you turbo for shaft play and also make sure the blades are all ok and not damaged, on both wheels.

I would also change your plugs. Fouled plugs made my power drop off like a rock when steve kan was tuning it. Everyone thought i spun a bearing because of the power dropping off in high rpms. Change your oil and strain it to make sure. If you can, cut open your oil filter and look to make sure you don't have any copper bits in it. I would think you would have already known if you have bearing issues, but its worth a look.

 

What about the air temps or heat soak. Does it start out good and slow after first run and then slower the next run? Possible small boost leak getting bigger!

 

i changed the plugs at the track before my first run, my car has been getting slower every event 5/13 all passes in 120's 5/27 119 6/3 117 + 114 mph. the motor seems good idles fine , and has 360 vacuum on power fc which is where it normaly is. the air temps where a little higher but nothing crazy. don't know why the car is losing power? thanks for the help

 

Maybe check for vacume leaks.....I had similar problem and when I plugged up the turbo with a PVC cap and put an aircompressor fitting in it, I found lots of leaks to fix! I was also able to figure out at what point the Vband clamps would hold.

 

Part of it might be due to tuning in conjunction with the hotter intake temps as summer approaches. Are you monitoring AFRs?

 

I think you are losing boost somewhere, try to maybe pressurize the system and look for leaks.

Anthony

 

thanks for all the ideas, i'll check for leaks + watch my a/f ratio and see what happens

 

Check the simple things first. I know my car actually turns into a slug after the plugs have 3000 miles on them. The difference is huge after installing a fresh set of plugs. Make sure your air filter isn't collapsing and monitor your A/F ratio to see if the car is leaning out. Are your 60 foot times the same, what about your 330 or 1000? Analyzing the runs will enable you to be more specific about WHEN you are losing power...10 mph is a huge amount of power. Also, the MPH beams are located PAST the timing marker at the end of the track- if you stay in it for a split second more- your mph will increase. Also, check to see if you are getting full throttle and if the secondary butterflies are opening- remember- start simple.

John

 

I would check for boost leaks.