Win some cash!
Registered User
Joined: Jan 2003
Posts: 799
From: Breese, IL
sorry... got home around 11pm. i flat passed out when I got home last night... computer on my lap and all... I had every intention of posting...
Mike was right. We had some problems that we couldn't find yesterday. We tuned part-throttle on the street at up to 14psi without a hitch. The car went on the rollers and hit a mysterious rev limiter at 4800rpm (never took it that high on the street). 5 different attempts all stopped dead right there.
We eliminated the MSD box and the FAST rev limiter as being the cause. I stayed it it for 5 seconds after it stopped pulling on one run and it's still firing at 4800 rpm. It feels like it retarded the timing so much that it can't pull any more. We believe it's related to the inductive delay for the coils. It's set to 96 (what FAST recommends as default), but I haven't been able to find out what setting it needs to be for the northstar coil packs (delteq setup).
Anyway, the car runs and drives beautifully.I just need to fix this little rev limiter that's killing me. Then we can turn up the boost!
So, we never got the boost past 14psi, never ran it over 4800 rpm, and had a passenger side header leak (gotta replace those copper gaskets with the carbon fiber ones I have in the garage).
Here's the dyno graph:
Mike was right. We had some problems that we couldn't find yesterday. We tuned part-throttle on the street at up to 14psi without a hitch. The car went on the rollers and hit a mysterious rev limiter at 4800rpm (never took it that high on the street). 5 different attempts all stopped dead right there.
We eliminated the MSD box and the FAST rev limiter as being the cause. I stayed it it for 5 seconds after it stopped pulling on one run and it's still firing at 4800 rpm. It feels like it retarded the timing so much that it can't pull any more. We believe it's related to the inductive delay for the coils. It's set to 96 (what FAST recommends as default), but I haven't been able to find out what setting it needs to be for the northstar coil packs (delteq setup).
Anyway, the car runs and drives beautifully.I just need to fix this little rev limiter that's killing me. Then we can turn up the boost!
So, we never got the boost past 14psi, never ran it over 4800 rpm, and had a passenger side header leak (gotta replace those copper gaskets with the carbon fiber ones I have in the garage).
Here's the dyno graph:
Last edited by Roadie; Apr 19, 2007 at 09:10 AM.
Registered User
Joined: Dec 1999
Posts: 1,791
From: Upstate New York,USA
Thanks for posting Roadie! Sorry you encountered the issue but that's damned impressive to have those numbers at 4800 rpm. So, you think the spark is being blown out by the boost?
sorry... i flat passed out when I got home last night... computer on my lap and all... I had every intention of posting...
Mike was right. We had some problems that we couldn't find yesterday. We tuned part-throttle on the street at up to 14psi without a hitch. The car went on the rollers and hit a mysterious rev limiter at 4800rpm (never took it that high on the street). 5 different attempts all stopped dead right there.
We eliminated the MSD box and the FAST rev limiter as being the cause. I stayed it it for 5 seconds after it stopped pulling on one run and it's still firing at 4800 rpm. It feels like it retarded the timing so much that it can't pull any more. We believe it's related to the inductive delay for the coils. It's set to 96 (what FAST recommends as default), but I haven't been able to find out what setting it needs to be for the northstar coil packs (delteq setup).
Anyway, the car runs and drives beautifully.I just need to fix this little rev limiter that's killing me. Then we can turn up the boost!
So, we never got the boost past 14psi, never ran it over 4800 rpm, and had a passenger side header leak (gotta replace those copper gaskets with the carbon fiber ones I have in the garage).
Here's the dyno graph:
Mike was right. We had some problems that we couldn't find yesterday. We tuned part-throttle on the street at up to 14psi without a hitch. The car went on the rollers and hit a mysterious rev limiter at 4800rpm (never took it that high on the street). 5 different attempts all stopped dead right there.
We eliminated the MSD box and the FAST rev limiter as being the cause. I stayed it it for 5 seconds after it stopped pulling on one run and it's still firing at 4800 rpm. It feels like it retarded the timing so much that it can't pull any more. We believe it's related to the inductive delay for the coils. It's set to 96 (what FAST recommends as default), but I haven't been able to find out what setting it needs to be for the northstar coil packs (delteq setup).
Anyway, the car runs and drives beautifully.I just need to fix this little rev limiter that's killing me. Then we can turn up the boost!
So, we never got the boost past 14psi, never ran it over 4800 rpm, and had a passenger side header leak (gotta replace those copper gaskets with the carbon fiber ones I have in the garage).
Here's the dyno graph:
Registered User
Joined: Jan 2003
Posts: 799
From: Breese, IL
I doubt it... I chose a non-projected NGK plug for that reason. It's a NGK 4554 gapped at .030" with Delteq and MSD DIS-4. That should be plenty of spark for any kind of boost.
At 4800, it's still sparking because it don't drop RPM. It just goes flat there and stops increasing RPM.
At 4800, it's still sparking because it don't drop RPM. It just goes flat there and stops increasing RPM.
Registered User
Joined: Jan 2003
Posts: 799
From: Breese, IL
Nah... This thread can go to rest. I'll start something new when everything actually works. 
Here's a video of one of the runs I made. They were all cut short at 4800 rpm.
http://www.lt1.org/turbo/dyno.avi
PS. Yup. that was a misfire early in the run. That has been fixed...
Here's a video of one of the runs I made. They were all cut short at 4800 rpm.
http://www.lt1.org/turbo/dyno.avi
PS. Yup. that was a misfire early in the run. That has been fixed...
Thread Starter
Registered User
Joined: Feb 2002
Posts: 5,645
From: Bridgewater, MA
Damn that engineermike 
jered, its seems to spool a little slow... especialy for a T76. What was he timing at with the dyno sheet you provided. I think those intercoolers arent helping... seems like you would only peak at 500-525rwhp if that 4800rpm run continued
Do you think that its pulling timing waybefore the 4800rpm which hurts the curve? Peak torque should have been around 3000-3500rpm, not 4500rpm. How does it pull on the street?
Jon
jered, its seems to spool a little slow... especialy for a T76. What was he timing at with the dyno sheet you provided. I think those intercoolers arent helping... seems like you would only peak at 500-525rwhp if that 4800rpm run continued
Do you think that its pulling timing waybefore the 4800rpm which hurts the curve? Peak torque should have been around 3000-3500rpm, not 4500rpm. How does it pull on the street?Jon
Registered User
Joined: Jan 2003
Posts: 799
From: Breese, IL
the dyno isn't creating enough load to build boost... On the street, I could hit 14psi by 3000 rpm. On the dyno, it didn't hit 14psi until ~4300. Timing started at 30* at 2psi at 2300rpm and dropped steadily to 24* at 14psi (we were playing it safe for pump gas).
I was shooting for a perfect street tune moreso than pure dyno numbers.
I was shooting for a perfect street tune moreso than pure dyno numbers.