just scratchin my head

chicken

chicken

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last night at cordova MWB finally got the thundermark to the track, and were still disappointed with the times. for those that dont remember/know its a 95 t bird with a 95 (i think) markviii dohc (stock internals) kooks headers, 3500 (maybe 3200) stall, jmod, 4.10's, drag radials and a 190 fuel pump. we want to see 13.99999999999 but it wont break out of the mid/low 14's. watching the car at the track it seemed to lag a little on take off and about the 1/8th mile it also lags again (also it was around 45-50 track temps). were running the IMRC's with a msd window switch, thought we set it at 3k. what i was wondering was if there would be any benifit to changing the rpm at when they open............dunno i was just sitting here thinking maybe if we made them open earlier or later maybe this would resolve lag and finally get that damn thing into the 13's, looks like we can actually need to adjust something next test and tune.

if anyone has a vid from last night please post it, and if MWB if you could post your times that would also help and correct any thing i have wrong or forgot that was done
 
wow 50 views and no comments yet, i understand this isnt necessarily a common problem since we cant with our cars, but with the thundermark we can!! and it there is a advantage to changing when they open it is possible to configure the window switch to a stock mark (gen 1) for a few extra ponies
 
do a compression and leak down test. also put a wideband on and make a run. that 190 could also not be pumping enough fuel for the mods you have. what is controlling the car? like what ECU are you running?
 
runnin the bird pcm reflashed to run on a dohc when we dynoed it it didnt go lean even with the old pump (stock sohc pump with 185k on it)
 
What's the torque curve look like? That's what I would judge by when to open the IMRCs. Seems with 4.10s and stall converter. 3 grand would be about right.
 
Timeslip would be helpful. Lag on launch....what kinda 60' we talkin.

Can't see the IMRCs being the problem unless they aren't openning. They should be open the entire time as you should never be even close to under 3k ever in the pass. With the stall converter even from the line they are likely almost open immediately.
 
the imrc's are controlled by a msd window switch triggering the stock solenoid, ill have to call him and have him post a slip. it was obvious when it happened (from outside the car) he would leave and the car would sound like a constant rpm then it would pick up and he said around the 1/8th (i think he said it was when it shifted into 3rd) it would kinda seem to not pull hard for a sec or so
 
02LSE96LSC91SE84TC said:
Can't see the IMRCs being the problem unless they aren't openning. They should be open the entire time as you should never be even close to under 3k ever in the pass. With the stall converter even from the line they are likely almost open immediately.
Click to expand...

+1. Check to see if they are opening and staying open. If they are it's not your problem.
 
Sorry Ive been slow to post, but here are my two fastest that night
60 ft- 2.103
1/8- 9.284@75.28
1000 ft- 12.123
1/4- 14.513@94.57

60ft- 2.141
1/8- 9.356@75.30
1000ft- 12.190
1/4- 14.574@94.83
 
Why don't you just disconect them so they stay open all the time for a run and you can rule out that they are or are not opening....
 
never thought about that kid, gen 1's stay open with the solenoid disconnected right? might be worth a shot
 
seems that you might have em opening too soon, based on the info you are giving...

try putting a 3500 chip in the window switch.
that is probably what is making it bog.. if I had to guess.

Can you datalog IMRC's and Accleration Rate?
that'll tell you if they are "helping or hurting" at the current opening RPM
 
XLRVIII said:
seems that you might have em opening too soon, based on the info you are giving...

try putting a 3500 chip in the window switch.
that is probably what is making it bog.. if I had to guess.

Can you datalog IMRC's and Accleration Rate?
that'll tell you if they are "helping or hurting" at the current opening RPM
Click to expand...

thats the beauty of this window switch, no chips/pills i just gotta hit the button a few times. no datalogging on the imrc's since the computer doesnt even know they are there (tbird puter has no output for imrc's hence the window switch)
 
ok, cool that makes sense.. dunno why I didn't grasp that from the original post..

THEN.. datalog acceleration rate and use different IMRC opening points until you get the least amount of decrease in acceleration rate..or the largest increase in Accel Rate.

that'll tell you IF they are helping or hurting and help you get em dialed in.
 
chickenviii said:
no datalogging on the imrc's since the computer doesnt even know they are there
Click to expand...

I think I "MIGHT" have figured out why this "lag" is occuring.

I opened my SCT PRP and looked in the spark section, there is a spark adder for when the IMRC's are open.
at high load at 3K above there is a fair amount of spark being added.

Since the PCM doesnt know about the IMRC's your gonna have to "get creative" to get the correct amount of spark added to the right load and RPM points.
 
XLRVIII said:
I think I "MIGHT" have figured out why this "lag" is occuring.

I opened my SCT PRP and looked in the spark section, there is a spark adder for when the IMRC's are open.
at high load at 3K above there is a fair amount of spark being added.

Since the PCM doesnt know about the IMRC's your gonna have to "get creative" to get the correct amount of spark added to the right load and RPM points.
Click to expand...

Thats what I was trying to say in post #11.
 
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