What can cause this:

[mulot30th]

Supercharged sled apex

STRAIT VP C16 fuel
Engin compression ratio it 10-1

At 20 # of boost:
With meth injection turned on or off will run perfectly and boost needle is stable


At 24# of boost:
With meth on it does misfire and send a lot of flames strait through the exhaust and make no power and boost needle bounces around a lot

With meth off, it does not misfire and run correctly and boost needle is stable


At 27-28# of boost:
With meth on or off no mather what I do with air fuel or timing, it does make LESS power than 21# of boost and missfire badly (almost sound like a stutter)
Boost needle bounces from 26-29 psi all the time


At 30# of boost, same thing, no power...
Boost needle bounces around the 27-31# all the time



Plug gap is 0.020"

I use the SDS-EFI ignition coils.
Air fuel ratio are in the mid 11' range. but tried low 11's to low 12's with same results

 

[heath@mpi]

You are flooding the spark and blowing it out this is why it does it on high boost with meth but noth without.

The coils are not strong enough.

 

[mulot30th]

Coils are suposedly 40kv discharge voltage.


But... can it be plug wires?


the wires are regular gm saturn 7mm resistance wires.


I measured them and they show between 1100 ohm (shortest) to 2090 ohms(longest) resistance.

should I try some race wires or at least ones with less resistance?

 

[mbarryracing]

Has it always done this, or is this something that just started happening?

 

[mulot30th]

always I never have bee able to race it a full boost

I tried many many times but.... not with great results.

 

[mbarryracing]

PM'd you...

 

[mulot30th]

pmd you back!

 

[TurboJamie]

Im willing to bet that if you put stiffer valve springs in the problem will go away. It has nothing to do with blowing the spark out. Your floating the valves plain and simple.

 

[mulot30th]

make sense...

anyway... I am ready to try just about anything until it works...


because once it works and I can go full boost...


the mph will go up!

 

[onestopjim]

Im willing to bet that if you put stiffer valve springs in the problem will go away. It has nothing to do with blowing the spark out. Your floating the valves plain and simple.

NOT the springs, I have ran stock springs to 40 pounds and 11000 rpm.. springs float about 15000 at that time you will bend valves..

 

[Wildman]

Supercharged sled apex

STRAIT VP C16 fuel
Engin compression ratio it 10-1

At 20 # of boost:
With meth injection turned on or off will run perfectly and boost needle is stable


At 24# of boost:
With meth on it does misfire and send a lot of flames strait through the exhaust and make no power and boost needle bounces around a lot

With meth off, it does not misfire and run correctly and boost needle is stable


At 27-28# of boost:
With meth on or off no mather what I do with air fuel or timing, it does make LESS power than 21# of boost and missfire badly (almost sound like a stutter)
Boost needle bounces from 26-29 psi all the time


At 30# of boost, same thing, no power...
Boost needle bounces around the 27-31# all the time



Plug gap is 0.020"

I use the SDS-EFI ignition coils.
Air fuel ratio are in the mid 11' range. but tried low 11's to low 12's with same results

I agree with Heath that your probably blowing the spark out. I also agree with Jim that your not floating the valves at 24# or even 30# (this is normally rpm based). The reason your blowing spark out at 24# with meth and not without, is meth needs a leaner A\F (its adding more fuel overcoming the spark sooner). Either way your losing spark, could be wires, could be the coils, could even be the stator. Wires are the cheapest to change.

 

[mulot30th]

I will do just everything... so I'll insure this problem goes away next winter... I don't want to chase this next winter.

For now I just re-installed my low boost (22 psi) pulleys... so I will run the blower more efficiently than having it geared for 30 psi and dumping to 22 psi like I did until now.

 

[Blue shadow]

Are you running the stock block ?I was thinking of getting one of Daves block next year.Running 20 to 22 psi put a lot of heat to the block .When you get some thing fix there is allways something right behind it to take its place?There is no end to it.

 

[mulot30th]

I run hurricane block.

Right now I am stukc to running tne 19 psi pulleys... since any try to go higher boost result in backfires and unburnt fuel going strait thru the exhaust.


As I said, I will do just about everything that my imagination can think is possible. because I dont want this sled to do the same next year...


This is extremely frustrating... EXTREMELY to have the engine to take boost, to have the blower to make boost.... but not being able to make anything with that boost.

 

[mulot30th]

Can not having enough/too much timing do this?



Just asking... I don't think so... but never know.