I've been thinking..........is it possible detonation could occur with 0* timing?? I don't see how it could since yer not starting the flame front til after the piston is headed back down. Then again I don't see how it has enough time to happen with 5*. The only thing left would be pre ignition from a hot spot but I don't see it being that either because I get knock from just revving it up sitting still just as soon as I start it up. What do yall think?

I will be fixing up a gasket for the blower when I get off work today and will post up the results later tonight.

 

Just so you know ford didnt use knock sensors on the 03-04 cobras because the blowers were to noisy. i would chuck it up to false knock spend the whole 200 bucks and let Alvin from PCMforless send you a tune before you are buying a new motor along with that tune.....

 

Have you compared 92 octane to 110 octane yet? That would tell you pretty quick if it's real knock. If it gets any better with 110 then you know what's up. If it doesnt change then you know what's up. Either way you know what's up.

 

This might sound stupid but... my dad worked for GM for awhile and one time he hooked the knock sensor wires to the tape deck and you could hear every noise the motor was making... pretty cool really... sounded just a like a really good microohone but all you heard was the mechanical noise not everything else like exhaust... kinda of strange to hear actually.

you could hook that up to a recorder or something while you make it knock then play it back and listed for spark knock. A video camera would work with the audio input ports. You'd be suprised how clear it is.

 

I remember reading the other day about the ford blower cars not having knock sensors, must be something to that. I'm not wasting $200 on a tune until I know if it's false knock or not.

The highest unleaded octane I can get around here is 102, I even ran E85 for awhile which is 105 octane and still got the same knock.

I may have discovered something just a few minutes ago.......I put the blower on with the thick gasket and teflon washers under the bolt heads and then turned the key on motor not running with datamaster running and took a wrench and pecked around on the blower and still got knock (I've done this in the past to see how sensitive everything is). So I doubled the gasket which is now about a 1/4" thick and it still showed knock, but I did have to tap it alot harder to get knock. Well I pulled the blower off and decided to tap around on the top of my intake, which I've never done before and the knock count started going crazy, I'm talking just barely tapping it. Obviously the top of the intake is suuuuuper sensitive, it's waaay more sensitive than the headers ever thought about being. You can actually hear it ring through out the entire motor, I may be on to something here folks. I've gotta figure out what to do to deaden the top of the intake, any suggestions??

 

Since the intake is essentially a holow tube... it makes sense tapping it would make alot of noise... interesting

Ford must have given up on trying to silence it.

The new Vette SS Blue Devil whatever is supercharged along with a bunch of GM FWD cars, but those blowers are silent...

Do you have an intercooler under the blower? I bet that helps give structure to the intake reducing ring and act as a muffler by removing the ring/sensitivity.

One way to reduce ringing on pipes/rods is by grabbing them with something soft... think about clamping it with something soft.. ha yea right..

 

Yeah I built an intercooler and it's actually bolted to the underside of the top of the intake. You would think that would help with the ringing but obviously it doesn't. Right now i'm stumped on what to use to dampen it. I thought about using some kind of rubber coating on the underside of the top, I dunno.

 

Just pulled the intake off and that aint what's ringing. Tapped on the heads and it rings just as bad without it on. It sounds like it resonates out thru the headers and they are what I'm hearing ringing. Wonder if there is any kind of dampening "donut" you could put on the headers or exhaust somewhere?? Anyway, I'm still gonna coat the intake and use a thick gasket under the blower and see what happens. I'm almost tempted to just turn the damn knock sensor off.

 

well if you have been working on this car for 2 years i dont see how a 200 dollar tune is a waste..... you dont know what knock is or what it feels like if you have the timing as low as you do and you still think its knocking. it has to be false knock, no timing along with the fact you have put in high octane fuel and it did the same thing. Put a custom proven tune in the car, put it on a dyno, touch up the mail order tune and enjoy the car

Thats my 2cents

good luck.

 

I'm pretty sure I know what knock is bud. You might like to waste $200 but I don't. No it doesn't have to be false knock but that's what I'm trying to find out. I can't hear the motor ping for the exhaust, pretty simple to understand. And I think I know what my car needs more than a tuner hundreds of miles away that hasn't spent countless hours fabbing everything piece by piece and has never sat in the drivers seat, but thanks anyway.

 

If I was you I would put the one bar map back in the car set the timing back to stock and then subtract 1.5 degrees per pound of boost in the 85-100KPA portion of the table from 2000-7200 turn the knock retard to a max of 4 and then drive the car. I would hope you are tuning this car with a wide band you need to get the A/F to 11.5-12.0

 

Cars can continue to run with the ignition off, that means no ignition what so ever. That's because heat and compression ignites fuel all by itself... the name that give that is dieseling.

The reason diesel engines make so much noise is because they spark knock on each power stroke. Weirdest thing about that is they dont even have an igntition system, they rely on detonation (as you learned above = spark knock).

 

A diesel engine ignites because of the heat of compression... in effect, equivalent to pre-ignition, or "ping" on a gasoline engine. Detonation (knock) is not the same as pre-ignition. They are two different problems. Detonation is caused by a second flame front developing AFTER the spark ignites the mixture.

Both will damage your engine.

 

How many roots blowers do you know of sittin under the stock hood of a 4th gen F body and under the unhacked cowl? .....So I basically have nothing to go on as far as tricks and shortcuts so that's why I'm here trying to get ideas. The one about cobra's not running knock sensors was great news for me actually, didn't know that til I posted up here then did a lil research on it. But you can bet yer *** Ford made damn sure it was false knock before they decided not to put knock sensors on them.

Second, about the roots blower...... look up adiabatic efficiency then you'll know what I'm talking about. Adiabatic effiency: occurring without gain or loss of heat. A roots blower at best is about 50-55% efficient, a centrifugal can be as much as 75-80% efficient. That's a whole lot less heat than this roots I'm running therefore you can run 9 lbs of boost on a stock LT1 where as I can't unless I intercool the hell out of it. I'd bet this roots blower is a helluva lot louder than that centrifugal you have too, not just the whine but mechanically speaking. Also, a roots blower is pretty much instant full boost as soon I open the throttle, it doesn't gradually build pressure like a centrifugal. So that means if I'm puttin along at let's say 2500 and nail it I've got 5-6 lbs of hot [edit] air being shoved into a 10.5:1 motor at a very low rpm and that's a really good recipe for detonation.

I really don't feel like burning up my pistons or hammering my rod bearings til they fall out .....

 

OK.... stop fighting like a bunch of little kids, or the whole thread is going to be deleted. Personal insults are not allowed, and "infractions" will be given if they continue. Get enough points, and your account will be closed.

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