nitrorocket

iTrader: (12)

Well, I was noticing right around 6500 rpm with 9psi, It always felt like I was hitting the rev limiter and would not rev any further. Today on a trip to the store, I turned the boost to 11 psi and picked a ton of power, but now it hit the "rev limiter" at about 6100 rpm and would not rev any higher. My rev limiter is set at 6800 rpm. I am sure it must be spark blowout.

There goes trying the boost at 14 psi untill I get this fixed.

Soooo, instead of trial and error.... who else has had this happen and what was your trick on the ls1?

I run the 6.0 truck coils and MSD wires. I run TR6 plugs with .035 gap.

JZ 97 SS 1500

iTrader: (2)

I run mine at .025 to avoid spark blowout at 16psi.

Jose

Tiago

iTrader: (27)

it can be a lack of fuel too.

look at the tune.

SS2win

iTrader: (11)

nitro, if you went by the custom os upgrade instructions and scaled the boost table by 300% then your putting in way too much fuel. I thought I screwed something up bad until I scaled at 100% and then tried 50%. Only then could I begin to tune and it was still hitting 9:1 when the boost came on. ugly but a bit of CYA from efilive.

nitrorocket

iTrader: (12)

I figured out the 300% factor was wrong the fiirst time out and rescaled the boost map. My AFR's are dead on at labout 11.3:1 AFR all the way up on my datalog. Then they just stop where they won't rev any higher. It just starts running real choppy and wont rev any higher, just like a rev limiter. It must be blowout I am guessing. I will close my gaps and see from there. I am a little dissapointed that it could be spark blowout with the truck coils and aftermarket wires. You can't get much better then that! I wonder if increasing spark duration would help?

This is a pain, I already have enough troubles getting the car to idle with the 96 lb injectors!

parish8

iTrader: (6)

i have been thru a few diferent ignition/missing problems. truck coils and tr6 plugs at .035 are good for me up to about 18psi and 6500+rpm. i dont think it is plugs or coils at just 11psi.

what valve springs?

what fuel? and how many miles on those plugs?

nitrorocket

iTrader: (12)

I am running 93 octane with no KR. Plugs look good. The heads are brand new TEA with there double springs. I have about 150 miles on everything. I have had this problem since the setup was first out on the road.

What timing are you running. For some reason I am seeing timing go to about 14.5-15.0 degrees at wot. I don't understand that because both high and low tables are set to 18 degrees timing. Could the retarded timing be causing this? I have read all past poss I could find, but no solid answers!

parish8

iTrader: (6)

i only run 14-15deg max, the 408 doesn't seem to need much timing.

i have ran into a leaded fuel problem but you are not running leaded. i have ran into a valve spring problem but you seem to have that covered too. now i am seeing a top end problem but only when i really boost it up to like 20psi.

no good ideas for you. right now with my problem i am going to put in a colder plug and gap them to .025 and turn up the spark dwell to 6ms up top and see if that helps.

nitrorocket

iTrader: (12)

I just loaded some new timing maps I got from Wait4me. On average the timing is higher all over then my stock map. I will see how that pans out and if it makes a change. I sure hope so otherwise I am at a loss. I really should not have spark blowout at 9 and 11 psi.

SS2win

iTrader: (11)

I'm running tr6 at 040 and no problems to 10 lbs.... also the timing map that wait4me posted on efilive is pretty aggressive compared to what i'm running...

nitrorocket

iTrader: (12)

Well, I got a chance to drive it again. I ran at 9 psi and 13 psi and both runs only reved to 6100 rpm. I added timing to 16 degrees total at wot. I moved afr's from 11.0 to 11.6 and it still did it. I am now gettin irritated! I found with 13 psi I can spin the tires and get sideways well over 100 mph!

Any more thoughts?

y2khawk

iTrader: (5)

Do you have access to dwell time in your tuning software? Some do, some don't.

If you do, what's it at?

we've got truck coils and car coils sparking into the high 20's, low 30's with anything from TR6's to "TR8's" with .030 to .035 gaps.

Pro Stock John

iTrader: (34)

Problem is ignition or valve float.

nitrorocket

iTrader: (12)

I JUST FOUND THE PROBLEM!!!

A huge downfall of tuning a car with stock pcm, especially in a non f-body car, is the 1 million tables you have to change. Going from stock parameters to a full out twin turbo in a Chevelle makes you have to change damn near EVERYTHING!!

I had checked all my rev limiters numerous times and was about to deactivate them when I noticed yet ANOTHER table! "FUEL CUTOFF LIMITERS IN GEAR" table. The in gear fuel cutoff rpm was factory default to 6200. Makes sense since it bounces from about 6180 to 6100 rpm. I will deactivate that. Awesome!

Also, it is unbelievable how much power 13 psi is on my setup. I have to be putting down at least 700 rwhp if not more. The car will leave rubber at 100+ mph!! It is actually insane to drive! Yesterday I got in my first race with a Mini Cooper, It was close, but I won! Amazing how clueless some people are!

Pro Stock John

iTrader: (34)

Sweet, so you will run 140+ traps like me?

I broke my tires loose at 475rwhp.

Congrats on fixing it, I have seen folks forget to modify that table.