Ford Mustang Forums banner

1 - 16 of 16 Posts

·
Registered
Joined
·
7,415 Posts
Discussion Starter #1 (Edited)
Just wanted to bounce some things off those that have "been there done that"

On the dyno my car hit a solid wall at 7200rpms. We checked everything and there are no rev limiters in play.

Tuner suspects my coil wiring isn't ample enough given my 6 series box is under the driver seat (I get it, it's pretty small) and when I told him my gap he suggested it was also too open, .034-.035. I'll drop it to .028. I'll get the gap handled and wiring done. But a new variable has popped up. In my Holley directions and MSD directions it shows the MSD box going straight to the coil. Holley has since (May) posted a revised version that shows a ground wire added to the coil straight to chassis. Any issues add this additional ground with an MSD 6 series box? Also I'm running a dual sync distributor if that matters.

Another element is I'm running an autozone special coil. The MSD TFI coil housing cracked and was arching spark to the strut tower the day before dyno day. I just replaced it with a cheapy. Any recommendations for a better quality coil? I've heard they pretty much all suck anyway?

I'm not looking to extend the RPM that much. I'd just prefer it hits the actual Holley rev limiter than a spark failure. Currently it's at 7300. (Had it at 7500 but obviously it never got there either.)

Other than that this thing rips and I'm happy as hell.

Thanks.
 

·
Registered
Joined
·
5,227 Posts
I had to close up my gap to .024 (I usually go with .022 now to be sure) in order to not get spark blowout. I had a 6 series box and it was garbage - it died like a week after the warranty expired. And it never ran right. I threw in an old Accel 300+ I've had kicking around since then. If I was buying an ignition now, I'd go with a Pertronix box - they have some of the highest outputs without going to a race box (the MSD 7 series are good; everything lesser is really garbage - there's a few videos on youtube where people take apart failed units - heck, the Summit boxes are made by MSD and are the same crap - there's a video or two of those as well). I run a Crane LX92 (iirc) coil. I miss my old Jacobs. That thing lasted for almost 25 years and would fire at anything over 7 volts (MSD boxes need over 9).

Have you taken your car to the track? I'm curious as to the Si trim's potential. How much boost are you seeing? What's your pulley ratio?
 

·
Registered
Joined
·
7,415 Posts
Discussion Starter #3
Just finished it, no idea on track times. Our local track closed two years ago so 500 miles away is Vegas. I’ll probably head out there this year but it’ll just be on autox tires.

Spinning it to 48,xxx 3.47” blower 7” crank. We didn’t hero pull it either. 7 hot runs in about 45 min then called it good. Hits 10psi
 

·
Registered
Joined
·
7,415 Posts
Discussion Starter #4
So, without making a new thread, on topic with this one. What does everyone prefer when running a single coil with an MSD 6 series box? Should I look at the newer MSD coils or just stick with the $30 part store special I have on it now?
 

·
Registered
Joined
·
5,227 Posts
When I had my 6 series, I tried an OEM stock coil and the Crane as well as a Jacob's coil. None of them did any better than the other. If the Terminator has dwell control, you could try playing around with that - up to a point. At 7,200 rpm you don't have much time to charge the coil. If I was you, I'd look into a better box, honestly. You're asking a lot from a fairly low-end product.
 

·
Registered
Joined
·
7,415 Posts
Discussion Starter #6
When I had my 6 series, I tried an OEM stock coil and the Crane as well as a Jacob's coil. None of them did any better than the other. If the Terminator has dwell control, you could try playing around with that - up to a point. At 7,200 rpm you don't have much time to charge the coil. If I was you, I'd look into a better box, honestly. You're asking a lot from a fairly low-end product.
Alright I’ll stick with the gap and beefing up the wiring and see where it goes. What would be the next step in boxes? I’ve got mine currently under the driver seat. Would like to retain that location.
 

·
Registered
Joined
·
5,227 Posts
MSD 7 series are actually decent. It seems they've cheezed out on their more consumer-level stuff over the years - those are built to barely survive. The 7 series components are more robust. If I was buying a new ignition box for my car, I'd look at the Pertronix stuff - seems to be nicely made and a nice middle of the road between the 6 and 7 series. But I haven't used Pertronics boxes, just done a bunch of research.

BTW, it looks like you're about 100 hp down from where you could be at 10 psi; perhaps more. Are you pulling a lot of timing? What fuel and any charge cooling?
 

·
Registered
Joined
·
7,415 Posts
Discussion Starter #8 (Edited)
Non intercooled. Last dyno pass was done after 7 consecutive pulls in about 45 minutes. It hit the timing/temp retard at around 6500. Never did a cool off hero pull. I wanted to run the car in hot heat soaked condition so it would be dialed in for open track/autoX. Pulls timing at around 230 intake temp. Had we let it sit for 20-30 min numbers would have been very different. Base Timing is around 17* (before the retard). On the log that 622 run was when it pulled timing back to 11.
Fueling is fine. 60lb injectors, 49-50psi holds for the entire pull. Injectors are around 82% duty. AF after 5000 is around 11.0. Goal was longevity. I’m actually thinking about putting a 3.60 pulley on to slow down the blower and drop temps a little bit.

Next time our club does a dyno day I’ll go back and let it cool and drop a hero pass.
 

Attachments

·
Registered
Joined
·
5,227 Posts
The timing is the culprit. I think you misunderstood the fuel part of the question - not is your fueling ok, but what fuel are you running? BTW, 230* IATs are nuts. I pull timing starting at 140... Where are you taking your intake air from? I did a cold air intake test once - check out the difference:

 

·
Registered
Joined
·
7,415 Posts
Discussion Starter #10
The timing is the culprit. I think you misunderstood the fuel part of the question - not is your fueling ok, but what fuel are you running? BTW, 230* IATs are nuts. I pull timing starting at 140... Where are you taking your intake air from? I did a cold air intake test once - check out the difference:

Oh, 91 octane. Air is coming in via Andersonpower pipe, 4” filter inside the fender. When I log open track 210-230 is the norm. I’ve thought about going air to air but I don’t want to cut up the front end for an IC and also would rather that air get to the radiator first. I could easily slap a meth kit on but that’s something else to fail. I had one years ago and got sick of it. I knew I’d get flack for my numbers but I’m not worried. This power level in ****ty conditions will still be more than I need.
 

·
Registered
Joined
·
31 Posts
Oh, 91 octane. Air is coming in via Andersonpower pipe, 4” filter inside the fender. When I log open track 210-230 is the norm. I’ve thought about going air to air but I don’t want to cut up the front end for an IC and also would rather that air get to the radiator first. I could easily slap a meth kit on but that’s something else to fail. I had one years ago and got sick of it. I knew I’d get flack for my numbers but I’m not worried. This power level in ****ty conditions will still be more than I need.
Is it not pulling or is it hitting a rev limiter? Should be odvious. Old school
6al with a 7,500 rpm chip. Pulls to 8,000 no problem. If it’s the old school box like I have. If not so Others had some not so accurate “pills” or “chips” that were not exact.
 

·
Registered
Joined
·
7,415 Posts
Discussion Starter #12
No chip in the box at all. Holley rev limiter was at 7500. 7200 it was done finished pretty hard. Regapping plus tomorrow. Might go out to middle of no where and see where it’ll go.
 

·
Registered
Joined
·
5,227 Posts
Well, that makes sense. I think an A/A in your case would be a great idea and cheap insurance for an expensive motor. Even a procharger deal or something similar would be better than nothing.
 

·
Registered
Joined
·
3,649 Posts
Wow you air temps are up there. I would definitely look at adding an intercooler. It will make more power, but safer which is more important.
 

·
Registered
Joined
·
7,415 Posts
Discussion Starter #15
Wow you air temps are up there. I would definitely look at adding an intercooler. It will make more power, but safer which is more important.
With what I'm doing with the car, I'll go up pulley size again. I know I can keep 550 cool enough to be fine. I'll be learning real quick once I hit a session with this new setup. Overall cooling is my biggest concern. If I get cooler IAT's but lose efficiency with the radiator I've gone backwards, more HP means more cooling needed. I've had to totally re-think HP stuff ever since I got into open track. If this were a street/drag car I'd put meth back on the car and go for all the HP I could get.
 

·
Registered
Joined
·
31 Posts
It sounds like it is probably the boost blowing out the spark with a gap more in line with a naturally aspirated combo like I have. It’ll be interesting to see how the wiring and shortening up the gap work. It’s possible the plug gap alone will get you another 2 to 300 RPM I would imagine.
 
1 - 16 of 16 Posts
Top