Stephen Max

iTrader: (59)

I've been carefully going through some WOT runs since installing the 3" pulley, gradually running it up to redline under full boost.

Well, I ran it WOT up to redline in 1st and 2nd gear yesterday and heard some detonation just before I hit redline in 2nd. I let off the throttle immediately, and to my relief there was no sign of engine damage when I pulled up to a stop and let it idle.

I didn't see what my fuel pressure was because I had my eye on the EGT, which went up to about 1400F and then suddenly dropped to about 1200F when I heard the detonation. This verifies a thread a couple of months ago about how EGTs will drop when detonation occurs because the exhaust gas heat goes into the piston instead of out the exhaust pipe.

So right now I'm not sure what the problem is. Did my fmu not funtion properly? Or was my fuel pressure so high that the pump couldn't provide enough flow at that pressure? The fuel pressure should have been up around 100 psi with the 8:1 fmu. Injector lock up, maybe?

At any rate, when my JWT ecu gets here and I'm running 370's at 43 psi I'll feel a lot better. For now I'm shifting when the mevi light comes on.

[maxi-overdose]

iTrader: (3)

I guess the only way to verify whether your FMU is working or not is to monitor the fuel pressure. IMO, FMU is quite simple and if it is broken, I would guess your EGT will raise very fast and hit the limit before 10psi.

I guess it is the injectors that cannot deliver sufficient amount of fuel to the engine at 10 psi.

I remember reading Kevin's post that Jane was detonating on the dyno with a small pulley. 3.125 IIRC.

have you dynoed your car yet?

IceY2K1

iTrader: (3)

Good read! http://www.streetrodstuff.com/Articl..._Basics_VI.php

IceY2K1

iTrader: (3)

My advice is to get the intercooler ASAP or at a minimum buy a Aquamist WI system and run a water/alcohol mix.

I'd do both.

Chunger

iTrader: (1)

<whisper> J&S..... J&S.............. J&S................... </whisper>

ejj

iTrader: (5)

Really hot out?

Stephen Max

iTrader: (59)

Yeah, I hear you.

What I'm wondering, though, is will the timing retard and the 11.5:1 afr that JWT programs into my ecu be enough to take care of the detonation?

If it isn't, then I guess it's J&S time.

Stephen Max

iTrader: (59)

No, it was in the 80's. I was on the way home after driving a while, so the engine was good and warm, but my oil temp gauge was reading about 160F, so it wasn't blistering hot.

Chunger

iTrader: (1)

Ideally, if you get the JWT ECU... it should be programmed to "properly" have the fuel and timing advance necessary (and safe) for what you are running... of course that assumes that it will be a custom program.

Having the J&S would be an extra "SAFEGUARD" against other unforseen (and sometimes additional mods) factors.

Stephen Max

iTrader: (59)

It just occurred to me that I still have one step colder plugs in my engine. Maybe I should have changed to two step colder when I changed pullies?

IceY2K1

iTrader: (3)

Stephen,

It wouldn't hurt and *MIGHT* slightly help. Switching to colder plugs will help reduce combustion temperature some, HOWEVER the major advantage of colder plugs is reducing the plug tip temperature as a possible source of pre-ignition.

2-step colder plugs vs. 1-step hotter plugs helped slightly reduce the detonation on a vehicle I have that detonates constantly, however it doesn't make a drastic difference. Can't go any colder or they'll foul.

IceY2K1

iTrader: (3)

Most likely yes. I've read that JWT is known to be overly aggressive, ie safe, on his timing maps.

For maximum power, you'd be better off having JWT leave the timing alone and use a J&S to retard the timing to YOUR specific needs. Also, didn't Mardi say that the factory ECU and therefore JWT reprogrammed ECU, doesn't monitor knock and adjust timing under open-loop conditions? If so, you may still have detonation even with a JWT, so J&S might be the ONLY way to go.

JAY25

iTrader: (38)

He should be fine with the JWT ECU and the 370CC injectors, JW delays timing in a conservative manner therefor stuff like that does not happen. This guy I am removing his SCer possibly this saturday, hes selling the 370s and the JWT ECU supercharged programmed ECU, he has no FP regulator or FMU of any type and he has the 2.87 pulley with the intercooler. You should not need the J&S. If you dont believe me sit one day and talk to him, he would be more then happy to talk to you and explain how he tunes those ECUs

IceY2K1

iTrader: (3)

I believe you.

I'm just saying that every time I read about a JWT ECU, they say they are tuned very very conservative, ie safe, which is FINE by me, but not necessarily for max performance.

Now the question is whether the factory ECU or JWT tuned ECU adjusts timing according to the knock sensor in open-loop. I'm betting only extremists like Mardi, Nigel, Turtle, or Kev will ever truely have a need for the J&S.

Anways, talk to who? Clark Stepler or Jim Wolf or ?????

Turbo95Max

iTrader: (25)

hummm

supposely JWT disables the knock sensor feature on their turbo program. dunno if they do that for everyone but mine was disabled. and yes i know they do very conservative timing maps...based on opinions of many people AND personal experince.

feel free to call up JWT to ask them some questions, but make sure you have 20+ min to spare...haha

LatinMax

iTrader: (1)

Who do we get it from and do we ahve a deal on the price?

Chunger

iTrader: (1)

It was for our 1st (only?) GD here on the forum... forgot the price cuz I got the knock/retard/AF gauge too.

There were some from the GD that are trying to sell their "new" unit... check out GD with Search.

http://www.jandssafeguard.com/

LatinMax

iTrader: (1)

Thanks, I will.