Dang I would've thought that combo would pull to 6500 all day long, even my crappy 165s and F cam pull past 6k.

 

Yea I don't think it's the combo, something is holding it back from reving

 

does it seem to be breaking up or anything around that rpm range?

 

it peaks at 5500 right around max boost. then decrease to around 5250 while wot in 3rd.

i doesnt sound like a hard miss, it just feels like in decelerating i guess

I dont think its ever pulled to 6k. free reving with no boost and full pulls all kinds of testing to get it to rev etc it still wont pull

 

hmm,thats just weird so,it will rev to 5500 max,and even then..it will slowly drop rpm's to 5200 or so,while wot? do you have a good fuel pressure gauge and wide band? since you had this problem before you changed the cam,heads etc it looks like it must be something electronic? hope you get it sorted out!

 

thats correct and i have verified fuel pressure and air.fuel.

Maybe i have too cold of plugs?

using NGK -9 plugs

 

I use TR6

 

whats ur combo

 

357, f cam, holley heads, trick flow intake, twin SVO turbos, AOD. I just switched to e85 so hoping to hit 600hp myself next week on 15ish psi.

 

What fuel are you running again? If running E85, that is too cold of a plug, running gas don't need to run that cold of a plug unless running 20+# of boost.

 

E85 20psi

 

Go down to a #7 and try putting more timing in the motor, every motor and combo are different and they tend to like different timing curves. Mod motors like low timing on E85 and my 375 ci. like a lot of timing, you just need to tune to what your particular motor likes, also try to check the E85 you get, good luck and keep us posted.

 

Odd question out of no where, do you remember what brand/part number you put in the rear end to replace the pinion flange to yoke?
Thanks bud

 

Have you checked your valve springs? I was having a similar problem where it just seemed like it wouldn't pull past 6K. Checked the springs and the seat pressures were pretty low for a boosted car, down around 120lbs. I put in some new springs with much higher spring pressures (~170lbs on the seat) and now its pulling strong past 6500 rpm.

You could also check your spark plug gap. I had the same problem a couple years ago and had much too wide of a gap (.024). I narrowed the gap to .017 and it picked up nicely. Spark plug gaps are an easier fix, I'd check that first.

 

My heads came with some PAC springs that are supposed to be around 150lb on the seat. factoring in 20psi, maybe they need more pressure?

on the plugs, my gap was at .028. I just put in new plugs @ .025.

.017 seems crazy low doesnt it?

 

The gap really comes down to how strong of an ignition system you have, try 18-22 and see if it helps.
If it doesn't improve, then check the springs. The 150 would be fine if they have not lost any from that number when you have them checked.

 

how are you liking the megasquirt?

 

I thought so too, but the performance gain was immediately noticeable. Just had the car dyno'd at 25 psi and made 832/852 at the tire with the plugs gapped at .016.

I'd drop it to at least .020 and see what happens, its an easy and cheap thing to check. What ignition coil are you running?
If you don't notice a change maybe pull a couple springs and have them checked.

 

just an update.

650whp@20psi

tried plug gap at .018.

didnt help

 

I was having this exact issue. My coil was junk. It'd rev to 4700 and in the logs it just hit a wall. Replaced, she's all good now.