I went to the dyno last night for a tune on my new set up at 15psi. Everything was fine although disappointing exept for this issue. We were having like a misfire at 7600-7800rpm on every run. I changed out the distributor cap because the tower for the external coil was loose and I did a hack job installing it a while ago. That was not it. I threw in the new set of plugs gapped at .026in and it was still there. We then changed out the plug wires for a new set and yup, still there. The weird thing is that we could not see anything abnormal from the datalogs. The boost would fluctuate about .5 psi from 6000rpm to redline. We know it is not the dyno getting a bad ingnition signal because we could hear and feel the car hit some kind of limiter for a split second. I am annoyed with this on top of being disappointed with the power. Any advice is apreciated!!

My disappointment is that I switched over from my 60trim/ramhorn set up to my own custom topmount and sc61. My 60trim made 425@15psi although for some reason we had to pull about 2* of timing after looking at the plugs and power kept dropping when doing so.

Setup:
9.8:1 83mm CP/Eagles
DIY port b16 head (lol, made the same power after pulling timing)
Blox A cams and buddy club valvetrain
VictorX intake manifold with 70mm tb
1000cc Bosch Injectors
Custom Topmount with SC6152s
44mm Tial
3in downpipe and exhaust
MSD 6al
Hondata S300 with solenoid for boost control

Dyno graph by RPM. Signal cuts off.


Dyno graph by MPH. Notice the sudden power drop.


Previous set up: 60trim/Ramhorn @15psi You can see why i'm disappointed . I realize the sc61 spools later but damn!)

 

are you using a factory distributer? try the igniter and or internal coil.

 

I am going to suggest doing the same. I had a MSD 6a and had issues around the same rpm area. I got rid of the MSD and problem went away. I was and I am still using the same Blaster SS coil though.

 

try different coil/ignitor

what plugs are you running, and gap them down lower , i had mine at .022

 

I removed the internal coil from the distributor to use the Blaster SS external with the MSD. I am going to try removing the msd and running the external coil without it. If that still doent work I'll borrow a stock distributor.

I am using BKRE7 plugs. I dont think I need to gap them lower but i'll try that too.

 

with similar power i was running 8's

get rid of msd and use oem dizzy

 

I had a set of 7's with me from the last dyno but I also bought 2 sets of 9's. I will take the msd box out. Should I get rid of the coil as well? I dont have a stock coil for it anymore.

 

get a stock distributor. I've had MSD coils and MSD boxes go bad on cars while tuning. Stock ignition ftw

 

Will Do!

Would that also cause peak horsepower to drop or is the peak power on the graph what it will be regardless?


I dont want to start another thread so I'll ask here... Is there any way to keep boost semi-steady across the rpm range? Boost creeps from 13psi up to 15.3 and then drops to 14.6ish at the top. I was able to do so with my Profec B with the different settings. Obviously I would have a better powerband if I had 15ish psi the whole time.

 

Definitely try the OEM igntion setup.
Hey Edward, I PM'ed you.

 

Hey Mark! I replied to your PM. Thanks

I'll try the OEM ignition first.

 

I dont see where your powerband is lacking anything other than the dip, you didnt even make it to 8000rpm and it looks like its still making power..... find the issue and rev it out

 

I'd lose the msd.

 

It cuts out right before 8000 RPM, I think that's the problem.

 

Gap the plugs lower

 

The RPM graph goes to 7800 or so because the dyno stopped reading it after that misfire but it was actually revved out to 8700 or so. The dip in the MPH graph is where the RPM graph cuts off.

It just seems like torque dropped hard there but didnt quite recover afterwards. I added my dyno graph from my previous turbo set up.

 

i love all the msd bashing, if removing the msd stuff fixes it then fine, but i have had the same 6al on my car since 01. i have an oe dizzy with a blaster ss external coil and have had no issues. i did have a coil go bad but thems the brakes.

i am curious of the issue was resolved.

 

We've seen some cars love it, others don't. They seem to be quite hit or miss.

 

I am going back to the dyno tonight. When a coil goes bad its just dead right?

 

Yeah, the car wouldn't start at all.

 

Reminds me of the handful of guys running ebay turbos for 'years', while most other people have them virtually **** the bed in the first minute. I would never recommend judging a product by a single shining example. That's like saying stock WRX trannies are the most awsome boxes ever, since a single tranny took 450lb/tq w/o exploding like vast majority of the rest.


Technically speaking, a dead coil won't work at all, and a malfuctioning coil will do all sorts of crap - but will mostly break up. If it can't get the voltage or juice high enough, it eventually won't jump the gap at higher densities (boost levels).

 

I agree, do away with the MSD and try sotck ignition, and playing with the gap size on the plug to see if that help. i had a similar situation running msd, switched back to stock, #8 plugs gapped down to .020in, worked perfect.

 

So assuming that there is a problem here with ignition or whatever, nothing can be made of the comparison between these two dyno graphs? As in, comparing the torque or horsepower levels at 7k? At that point the SC61 should be doing more than the 60 trim, all of the technology is better. . .

 

Well, I was not able to get back on the dyno. I did unhook the msd box and ran the coil straight from the dizzy. Took it out on the street and the misfire was horrible. It would not go past 6500rpm. I pulled the plugs again to check them and noticed the gap seem large for .026 and it was!! They were all at .035!! WTF! I regapped them, put them back in and did a pull on the street. I could not feel or hear that misfire anymore and it pulled a lot more to where I had quite a bit of torque steer! so thats a good sign, but I need to get back on the dyno to make sure.

Would a larger gap affect the heat shown on the ground strap of the plug?

 

for around 400whp 7's are usually fine, above that run an 8 gapped to around .022