Had my car on the dyno this weekend, turbo GSR motor w/ stock ign system.

At anything higher than about 16 psi, the car started to miss a little bit from 7k rpm up... not a lot, just a miss or two with a few puffs visible out the tailpipe on the way to redline.

We changed the cap, rotor, ignitor, wires are new OEM, and nothing changed. I didn't have a spare coil on me, so I'm going to try that next, but does anyone else have any other ideas on what could be the culprit here? I really don't want to have to go to an aftermarket ign system or COP unless I absolutely have to...

Plug gap was gradually brought down to about .020 from .026 ish, no change in the missing up top

thanks


edit: Dyno Dynamics, you can see @ 7.2K and 7.8K where it missed and the power dropped off and came back up. Also yeah it seems laggy, i think the AVCR duty cycle was a little screwy. WTS AVCR




Modified by Toda Party at 9:59 AM 3/12/2008


Modified by Toda Party at 10:00 AM 3/12/2008

 

what heat range? im running stock dizzy, 6AL, blaster ss (nothing nasty) and 34 psi with 9's gapped at .018. no issues.

 

What are the A/F ratio? Did you put a new set of plugs on before dynoing?

Any pictures of the isolator?

 

r u tuning on crome?

 

Neptune

AF in the mid 11's

Yes we changed plugs

Temp 8's

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Toda Party &raquo;</TD></TR><TR><TD CLASS="quote">Neptune

AF in the mid 11's

Yes we changed plugs

Temp 8's</TD></TR></TABLE>

try nines, i had that problem until i got to 9's gapped at .024" also i think stock honda IGN is hit or miss, some people have great luck with it while others dont, i personally have had a lot of ign problem and cant wait to go COP...

 

Try one step higher and one step lower plugs.

 

not too thread jack but is it worth to get an msd cap and coil? maybe that might help keep the spark stronger

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by quicksilver1689 &raquo;</TD></TR><TR><TD CLASS="quote">not too thread jack but is it worth to get an msd cap and coil? maybe that might help keep the spark stronger</TD></TR></TABLE>

i too was wondering the same thing, the external Blaster SS coil with msd cap and rotor could all be had for $100 or less!! is it worth it? seems like the cheapest ign upgrade ive seen...

 

before he goes to 9's, where is his power? 8 may be too cold. and need 7's. and the gap has alot to do with it.

 

what cams r u runing?

 

guess i'll try temp 9's

i use 8's cuz you can get them from honda and they are easy to find, not too sure where to find temp 9s

power is 475 @ 15psi, we'd turn it up to 18 and it'd hit the 490's but it'd miss up top and make the graph all wavy/choppy and hard to tune

using 97 ITR cams

I'm gonna try using a different distributor and temp 9's and hope it works out...


i added the graph to the OP

 

gap hte plugs down... try 0.015.. 0.020 is too big for a stock ign system at 500hp

 

put resistor plugs in it...

 

i ran 7's up to 500. i think you may be too cold.
you do need to gap them down, and use resistors.

 

Gap them down and throw on an MSD cap with whatever external coil you want.
I was having problems with mine after leaving the tuner if I did a 1-4 pull. Top of 4th gear it would back fire from running so rich. Regapped the plugs to .018 and it's been fine ever since.

 

list your complete setup i.e. turbo, manifold, exhaust, etc.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boostedcivicsir &raquo;</TD></TR><TR><TD CLASS="quote">i ran 7's up to 500. i think you may be too cold.
you do need to gap them down, and use resistors.</TD></TR></TABLE>

i wouldnt use 7's for that power level

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDogg &raquo;</TD></TR><TR><TD CLASS="quote">gap hte plugs down... try 0.015.. 0.020 is too big for a stock ign system at 500hp</TD></TR></TABLE>

Exactly what I was going to say. Gap them down a bit more.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted k20 &raquo;</TD></TR><TR><TD CLASS="quote">

i wouldnt use 7's for that power level</TD></TR></TABLE>

i know i had to run 8's at 540, at the point i switched i cant remember.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blinx9900 &raquo;</TD></TR><TR><TD CLASS="quote">

i too was wondering the same thing, the external Blaster SS coil with msd cap and rotor could all be had for $100 or less!! is it worth it? seems like the cheapest ign upgrade ive seen...</TD></TR></TABLE>

The Blaster SS coil is no better than stock, they just cost a lot less and have a few hundred thousand miles and nearly a decade less wear and tear than the stock coil.

The MSD rotor is incorrectly clearanced to the cap and causes it to melt itself. All in all I'm not wholly impressed with the product line.

Hit and miss on stock distributor depends a lot on OE vs aftermarket (chinese) coil and ignitor aka avoid DK. I've seen all of one stock Honda ignition that needed to go below 0.020" plug gap, if the gap needs to be lower the coil is old and tired.

COP and such are expensive... spray a 35 shot and all your ignition problems will go bye bye.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted k20 &raquo;</TD></TR><TR><TD CLASS="quote">

i wouldnt use 7's for that power level</TD></TR></TABLE>

Why not? I run 7's in my personal car at 500hp, the burn is just fine.

 

The temp of the plug isnt going to affect a misfire like this...it def doesnt need to go colder, but warmer isnt going to help a mis.

Its def a weak spark...the car had no misses at a .035 gap and 12.5 psi...at 15-19psi even gapping the plug to .024 made small but minimal improvements. I've had stock ignition cars at 24+ psi and a .030 gap without issues.

This was C16 as well...FWIW

Jason, did you swap coils yet?

 

What size injectors are you using and what's your duty cycle? I know we had a car tuned with 550's with an 18g and it was missing at 24 lbs. Found out the duty cycle in the cold was all the way up to 100%. Threw some 750's in there, and the popping all went away.

 

i had a similar problem on a stock gsr motor running around 350whp. We tried lowering the gap to around .020 and it still had issues. It took 3 distributors before one kept it from missing. Its a hit or miss sometimes(literally )