vandal0-0

iTrader: (3)

I have a 408 with Dart 225 heads STS turbo 16lbs of boost water meth injection and front mount intercooler.9.1 compression tr6 plug .030 gap.When you first drive the car you can run it all the way threw 3rd gear for like 2 to 3 plasts on the highway and on the fourth time or so it detonates so loud its unbeliveable.Also have 2 Walbro 255 in tank stock lines and filter to the front with fmr,fuelrails,60lb injectors and fuelpressure hits 75lbs under boost.Need some help thanks in advance.

stevieturbo

Your tune is wrong....simple as.

Who is tuning it for you ? if the fuelling is right, and ignition timing set properly, detonation should not be an issue.

DeltaT

iTrader: (5)

First thing is to never run it into detonation knowingly again. Once is bad enough, twice to confirm what's going on is repeatable, then never again.

I would look for a cooling issue where you log your coolant temps as you go through a couple runs. I would also look into adding a fuel pressure transducer so you can datalog fuel pressure during your runs. Maybe check fuel temps as well.

How do you have the twin pumps set up? A T into one line or what? Return line, regulator, etc.

Jim

slowredz

iTrader: (23)

Put that thing on the dyno and quit doing that ****

vandal0-0

iTrader: (3)

The pumps are T together the car dont detonate on dyno just on street.I just read something about removing pcv system and add a catch can.Because when I remove the front turbo pipe theres oil in it.So theres probably getting oil on pistons causeing detonation.Is this write or wrong.The fuel lines t and go to each rail then to the regulator then return.I live in St.Louis MO. so not to many choices for tuneing.The timeing was at 19 overall then was changed to 14 to see what would happen

slowredz

iTrader: (23)

Drive it on the dyno just like you would on the street and see if you can make it do it with a wideband on it of course. Not just doing pulls...

Navy David SS

iTrader: (13)

Detonation is "normally" caused by:

1) Bad tune job
2) To much timing
3) Bad/wrong spark-plug (I'm using NGK-8's, you may want to look into them)
4) Bad gas (I just went through that, even with 114 octane you can get bad gas)

There is a difference between dyno and street/strip. You really should data log your street/race runs until you are absolutely sure of the tune.

I agree don't run it again until you have solved it.

David

abadz28

iTrader: (1)

it's probably the oil. Vent the PVC with a breather/catch can. I had the same problem with anything over 7lbs of boost.

1320

iTrader: (6)

first, what did it dyno? 60's on a 408 with 225 afr's.....uh, they are probably pretty close to done if its making the power it should. What turbo? not a 67? if so, its causing high air intake temps. Did the change from 19 to 14 do anything? And when you say you hear it, what are you using for diagnostics? wide band? egt? interceptor? hp? what?

Sabre_Logos

A few things that you need to look at:

1) What is the a/f ratio?

2) What are the coolant temps?

3) What are the intake temps at throttle body?

4) What does your ignition timing look like?

With your intercooler and water injection, I would not expect detonation unless something was way out of norm.

Slowhawk

iTrader: (12)

Put a wideband in the car and get a scanner you can log with. That will tell you everything.

All the cars we build like yours get Dynojet widebands installed if the customer likes it or not.Can save you a motor.

B4Cya

It may not be your only problem but the gases/oil from the PCV definitely lower octane and increase intake air temperatures.

vandal0-0

iTrader: (3)

The car only dynoed 560hp with a th400,air fuel is 11.8 to 12.0,the timeing table started in the 40s to 30s to 20s and ended up at 19 overall.Changeing from 19 to 14 the car still was pinging and pulling 6deg. of timeing on the scanner.The turbo is a T70.Running temps are 190s and the iat temp I think was In the 180s.

stevieturbo

Wow..those IAT's are pretty damn high !!!!

Are you sure they are correct ? Doesnt sound like either your methanol or intercooler are doing very much if IAT's are that high ?

1320

iTrader: (6)

180's! wow.....I ve seen 64 degrees with ambient at 95 degrees....76 turbo, meth, front mount air to air.....and 15 psi.

Even my old GN was 150 at 20 psi with just an air to air .
A T70.....? probably still to small. There are several variations also. a 76 is probably as small as I d run on a 408, infact a customer of mine has a 408, stock heads, with a 76 made 650 rwhp at around 11 psi I think.

ls1290

iTrader: (20)

180 temps and pump gas will detonation no matter how much meth is sprayed. You need to get those IAT temps down

Keith

stevieturbo

I dont see how he can be spraying meth, and seeing such temps....

Mine dont even get that high without meth !

HUNTER02SS

iTrader: (24)

I only see 130-135 iat on full run's data logging.Like everybody else said,get those iat's down..

vandal0-0

iTrader: (3)

What do you do to lower your iat temps

stevieturbo

OK...

firstly, where are you measuring intake temps ??

Because, it seems very odd, that you could have an intercooler AND methanol injection, and have such high temperatures.

Is the intercooler incredibly small ?