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Discussion Starter · #1 ·
Hey guys,

I finally got my BAD 6lb blower on the dyno today and here are the #'s:

369 RWHP and 394 RWTQ (blower)
297 RWHP and 339 RWTQ (NA)

There were no other changes made besides a Walbro fuel pump, NGK TR 6 plugs, and Bryan H programming. All runs done on the same Dynojet, although it was 15 degrees colder the when I ran NA.

Now for the problem. The first 3 runs were fine, but it was missing badly on the 4th run that we had to abort. the scanner said that it was missing on cylinder 1 & 2. The # 1 plug wire has a cut in it, but it had a cut for all 4 runs. Any idea why it started missing so badly?

The air fuel ratio was a little rich and did not lean out anywhere.

I would appreciate any suggestions.

Mike C
Portland, OR
 
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Discussion Starter · #2 ·
I forgot to add that it ran 13.3 @101 on a 75 degree evening with pretty humid air.

Does that ET sound right for the HP #'s?

Thanks,

Mike
 
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Discussion Starter · #3 ·
Originally posted by damc:
Now for the problem. The first 3 runs were fine, but it was missing badly on the 4th run that we had to abort. the scanner said that it was missing on cylinder 1 & 2. The # 1 plug wire has a cut in it, but it had a cut for all 4 runs. Any idea why it started missing so badly?
It was the cut wire that was making it miss badly. Sometimes it shows up, sometimes it doesn't. That's just the way it goes. Other possible culprits for #2 is too wide a plug gap.

FYI, DON'T RELY on A/F ratio on an ignition that is not up to par. I've seen a nice 13.0 AFR go to go 12.0 and under with bad wires/misses. Don't assume that its running rich. Fix your issues and go back to the dyno.

I've got a dyno queen. I can't seem to get a 12 out of it. Best so far is 13.06 @105.
 
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Discussion Starter · #4 ·
Hey Mike,
I think the RWHP #'s you laid down are pretty respectable with the PD and the 845 cam ( My personal opinion here !!!) On average you will gain about 15 hp per # of boost non-intercooled. Add to that you are using the 845, which is not exactly a blower friendly cam, and I think stock heads ??. Your HP increase would equal about 5#'s of boost..about right for your set-up I think !!

The missing issue needs to be addressed tho. First question, was it the PCM relaying the engine miss, or another means ?? If it was the PCM, the OBD2's are notorious for throwing missfire codes ( not sure if you have a conversion or not ) Did you feel the miss ??

Back to basics 101 here...ALL your supporting hardware needs to be in top working order if you are going to run boost (even in small amounts ;) ) Ignition, fuel...everything needs to be in he best condition possible to get performance...AND longevity out of your engine


All that said though, 369 RWHP is pretty respectable for a stock 350 with a relativly ineffecient cam for a blower, and 5-6lbs of boost.

SSee ya, Scott

BTW, here is a good site with a calculator for et and mph-vs-rwhp

http://www.smokemup.com/auto_math/index.php
 
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Discussion Starter · #5 ·
Thanks for the advice guys.

Scott, I have OBD II.

It was definitely missing badly. The dyno graph was all over the place and we could hear it missing.

My ignition system has less than 5k on it and should be in good shape. Do I need to step up to an aftermarket ignition? Any suggestions on what plug wires to go with?

Thanks,

Mike
 
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Discussion Starter · #6 ·
I'd definitely be using an aftermarket ignition with forced induction, especially since it gives you -spark- cut rather than -fuel- cut at the rev limiter...

For wires, magnecor all the way... $99 from www.lingenfelter.com
 
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Discussion Starter · #7 ·
Mike,
Knightshade is correct. Besides the better choice in rev limiter, an MS system will also keep the spark from "blowing" out under the higher cylinder pressures ;) I would also make sure you gap your plugs down to around .039"

FWIW, I ran an MSD 7AL, NGK TR6 plugs gapped to .035", with MSD wires with my PD unit. I never had any issues with spark.

If you logged any of the dyno runs, I would send them to Bryan to look at and see if he has any tuning changes that need to be done.

HTH, SSee ya, Scott
 
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