I'm planning some serious modifications for the future, although I would still like to use fuel injection (most likely a miniram) and the stock ECM with a custom PROM, and therefore I want to keep a knock sensor.

Will either the 305 or 350 knock sensor work in a Dart, Bowtie or Motown block, or would I just have to configure the spark curve by ear? It will be a N/A engine with forged pistons, but I still want the extra insurance. Thanks guys.

On another note, can I even use the stock ECM and fuel injection system with a 400+ cubic inch minirammed engine provided I get into PROM tuning, or should I go Holley or DFI...

Thanks guys.

------------------
1990 IROC 350
Mods: Too busy trying to make it run right to mod it.
Airfoil, Dynomax cat-back, MSD coil, 180 t-stat, Bald Eagle tires,
Hypertech fan switch, Accel 23# injectors, Holley module, ported plenum,
Ported Daytona Yellow stock base, Moroso valve covers, other stuff,
Streetdampr, Ruger P95DC, hot wife, new oil filter, !cats, !TBC, !AIR.
18.0 @ 85MPH since I'm one big-a$$ MF
"It's better to have and not need than to need and not have."

 

Will either the 305 or 350 knock sensor work in a Dart, Bowtie or Motown block, or would I just have to configure the spark curve by ear? It will be a N/A engine with forged pistons, but I still want the extra insurance.
using the 400 aftermarket blocks will have the
core drains like the OE blocks. so the use of
the 350 knock sensor will work. your tuner will
hopefully be conserative on ignition timing
until runs are made to 'dial' the system in.
..can I even use the stock ECM and fuel injection system with a 400+ cubic inch minirammed engine provided I get into PROM tuning, or should I go Holley or DFI
starting point on 400 is 24-28lb injectors
depending on rpm, comsumption, and performance.
42-45psi adjustable regulator would be good.
unless you have the time to learn DFI and understand
EFI id go custom tuning.

 

Thanks man, but if the knock sensor is tuned to a specific frequency (detonation) as felt through the engine block, then how could a stock one work with a Motown block that is of a different material composition and bulkier internal dimensions?

What are you guys with non-stock blocks doing for a knock sensor?

I probably should re-phrase my second question...Is the stock control system (except for the injectors, knock sensor and EGR) capable of taming a 400+ cubic inch miniram-fed engine IF I program a PROM for it.

Thanks.

 

we use the 3900ohm knock sensor for the GM
TPI's we can dial in or out the retard based
on what kind of 'noise' we get. some use the
lt4 knock sensor as it is a little more forgiving
in frequency handling. or totally bypass the
sensore all together. but your tuner will not
like life. he will have to rewrite the whole
spark table. havent really run into a heck
of a lot of problems using aftermarket blocks
and knock sensors. small or big blocks...

 

If your change the dimensions of an object you will change its resonating frequency. This goes for bells tuning forks and engine blocks. If you change the block to a more beefy block then the knock frequency should change. The ESC circuit will pick a frequency out as knock or not knock. The frequency is generated by the vibrations that are exercised on the peizo electric crystal in the knock sensor. Basicly it works like this. The engine vibrates causing the crystal to change resistance. The frequency of that change is interpreted as knock or not knock. The circuit picks out specific patterns of frequencies that are known through testing to be knock. If you change the block to a radically different block then the frequencies produced by the engine will not be the ones that the circuit looks for. You could rattle yourself to pieces and the computer would not ever step in on your behalf.

All this is pretty cut and dry in theory but the real world is not always that way. My suggestion is if you change the block you should probably test to find out if the circuit will recognize knock in your new block. Do this by creating a small part throttle knock going up a hill. BE CAREFUL when you do this. Advance the timing a degree at a time until you either hear a knock or see the computer retard the timing. If the computer does not recognize the knock sensor then take it away. It would be worthless anyway.

As far as your tuner hating life I don't think so. Anyone you let tune on your car should understand that the knock retard parameters are separate and severable. Do not buy a mail order chip for your engine. Have it tuned locally by someone with a good reputation, an exhaust gas analyzer and a dyno. If you need a new block your are a custom chip that only someone right there with your car will be able to do. You could tune your own chip if your into that kind of thing. There are lots of people on this board that do it. I would advise that you start with stock engines and work your way up.

I guess the real answer to your question is I don't know. I seriously doubt anyone else here does either. To give you a straight yes or no answer you would have to have tried it at least five times with five different blocks and had the exact same result every time. There just are not that many high-po block, stock computer combos out there. Try it and see. Maybe you will discover something new.

John

Heart of Texas Power and Performance

 

Thanks guys. Actually, the tuner will be me and it looks like some uncharted waters for the next couple of years but when I get it down I'll be sure to post results. My buildup is in its infancy stages now so I'm trying to forsee potential problems with the wire harness/sensors/ECM from a stock TPI on a monster mouse down the road. But it will be worth it when it's all over. Thanks.

 

I wonder what happened? How did the knock sensor issue turn out?