increased boost, do I retard the timing more?

C

calitower

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Jan 3, 2004

#1

• Jan 3, 2004

• #1

my 95gt had an intake leak at the MAF...since I fixed it, my boost went from 4-5psi to 9psi. The car was dyno tuned for the 4-5psi. Now I get just a hint of detonation when I jump on it (especially when I'm in the 3-4k rpm area but it goes away about as quick as it started. I have the timing set to 10* The vaccumm is at -7 at idle..is this normal? Should I retard the base timing back? If I set the boost retard to 1.5 it gets better.
I have a msd distributor, 6btm and coil. pro-m 75mm, fms 65mm tb, gt40 intake and alm heads, 30# injectors, fms e303 cam, 1.7 rollers.
Any help would get great.
TIA

 

95snoozer

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Dec 14, 2002

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RCR

Jan 3, 2004

#2

• Jan 3, 2004

• #2

tahts a huge jump in power 4-5 pounds of boost.

do you have an FMU? 4:1?

definietly get it on a dyno and increase your FP or let someone tune it.

what is your FP at idle? and at WOT?

 

C

calitower

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#3

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• #3

the original FMU was I think 12:1..powerdyne sent me I think 8:1 for the 9psi set-up but not 100% possitive,,could dig through receipts.
My FP is 42 at idle...WOT, not sure. Dyno guy tells me as long as no detonation, should be good.
I'm more currious about what I should set the base timing too....8ish or 10ish.
thanks

 

S/CBlack95GT

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Jan 3, 2004

#4

• Jan 3, 2004

• #4

If you are increasing the boost then you should get the car back on the dyno. You really should not have any detonation problems unless something is wrong. I run 12 degrees of base timing with the retard on 1. I see 10psi at max power.

 

C

calitower

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Jan 4, 2004

#5

• Jan 4, 2004

• #5

i installed a msd-8455 did a compression check..all cycl are 147 to 151. The car idles at 700rpm ok with a e303 but when i drive it, the car seems jumpie and some jerking, specially if i try to maintain a constant cruising speed (say 40 in 4th). I'm wondering if the weights are set incorrectly in the distributor....but it did say for a 94-95. Do you run a msd8455? any idea as to what the proper setting should be?
Also, before i fixed a few leaks and installed the distributor, the vaccumm was at about -15 @idle and max boost was 5psi @6k...now idle is -7 and boost 9 easy at 5.5krmp.

 

C

calitower

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Jan 4, 2004

#6

• Jan 4, 2004

• #6

i'm also put in autolite 25's...not sure what this matters..if any.

 

VibrantRedGT

"STANGNET'S PENGUIN SMACKER"

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Jan 4, 2004

#7

• Jan 4, 2004

• #7

calitower said:

i'm also put in autolite 25's...not sure what this matters..if any.

Click to expand...

Couple of things.

1. You should be running a heat ranger cooler not hotter. I run the Autolite 3823's at a .030 gap with is two rangers cooler.

2. If you hear detonation now than turn the BTM up or just retard the timing a smibbage. I run my timing at 9 degrees and the BTM set on 2.5 right now. Fuel pressure it around 42psi and sees 11psi of boost. I run my BTM on that number until I get my chip reburned.

3. What weights in the distributor?

 

C

calitower

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Jan 4, 2004

#8

• Jan 4, 2004

• #8

I tried checking the timing advance and ran the rpm up over 4k and the timing mark didn't move away from 10* (SPOUT was removed).
I tried to run the scanner and key on eng off was good...i tried the eng run test and I can't get past the eng identifier code **** (8 cyclinder).
here's soem info on msd dist. and weights..
http://msdignition.com/pdf/pn_8350_8352_8354.pdf

i set the gap at .034..can the plugs make it run that pooly just idling or driving around without getting on the gas much?
oh ya...in cali we have cheap gas oct91

 

C

calitower

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Jan 4, 2004

#9

• Jan 4, 2004

• #9

how do i know if my distributor is out of phase?

opps..i think i need to have the spout plugged in $%#&@*

i'm wondering if when i did some major work to my car if i got the distributor in wrong. for some reason i think when my friend set the dist he used the front driverside cyclinder (#5) as number 1 instead of using number 1 on the front passenger side....but not positivel. That was a year ago...now i put in a new msd distributor and hooked up my 6btm and it runs rough. ALso i got the increase in boost...just not sure what's wrong.
could this mismatch still run but be rough?? how do i know if my distributor is in correctly? this kills me over this car..but i wanted a HO car

 

VibrantRedGT

"STANGNET'S PENGUIN SMACKER"

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Jan 4, 2004

#10

• Jan 4, 2004

• #10

Don't run the car hard with sketching timing. If your timing light has a dial, set it to 10. Pull the spout then start the car. Point the timing light on the pointer. You want the light to flash 0 on the pointer now.

 

94GTLaserRC

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Jan 4, 2004

#11

• Jan 4, 2004

• #11

What does "detonation" sound like?
RC

 

C

calitower

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#12

• Jan 4, 2004

• #12

detonation sounds like marbles in your motor when you have the motor under a load (lead foot)...it's the same thing as hitting the side of the motor with a sledge hammer if you can hear it while driving.

 

94GTLaserRC

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Ernan Says "here it comes... dushbag"

Jan 4, 2004

#13

• Jan 4, 2004

• #13

calitower said:

detonation sounds like marbles in your motor when you have the motor under a load (lead foot)...it's the same thing as hitting the side of the motor with a sledge hammer if you can hear it while driving.

Click to expand...

GREAT...Forward this reply to Buggampimp!
RC

 

C

calitower

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Jan 4, 2004

#14

• Jan 4, 2004

• #14

the timing is at 0 when i have the timing light set to 10 on the dial. i reset the computer..maybe this'll help...if not,i'll make an appt for the dyno tune.