I'm geting knock retard from my turbo t/a and I'm tring to get rid of it, On my scanmaster my bl while driving with little throttle is about 110 it jumps from 90-125. Now when I start to accel the bl jumps up to 137+ and I start getting knock the BL has been as high as 146 and my knock was 6+ now when I floor it my knock goes 10+ and I can hear it pinging, and smoke comes out the exhaust when I let off the throttle. My plugs all look fine I pulled them yesterday and my fuel pressure is at 46 psi with hose off. When I put the line on it drops to about 40 and increases under boost to almost 60 psi, I'm going to do a compression test tomorrow to see what it is but was wondering if the car is running lean and thats why it's knocking under throttle? Should I turn up the fuel pressure? What should my bl be when I'm accelerating? The car does smoke on start up, and It's about a quart of oil low after 1500 miles (just figured valve guide seals), Now after a few minutes of runing the smoke goes away. I hope this all makes sense, I'm new to all this and know I have a problem and tring to learn how to fix it. Any help or ideas on what could be causeing knock retard please let me know,
Will high BL number cause knock?
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turbot2112
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blm should be around 128, but as long as there not bottomed out or toped out at say 150 you should be alright.
turbot2112
Active Member
- Joined
- Jun 12, 2001
- Messages
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also, if you do a search on the board there is a better explanation on blm than the one i just gave you.
We need a little more info to be able to tell what's going on.
What boost are you running?
Pump gas? What octane?
What chip is in it?
Stock injectors?
What other modifications do you have?
Like turbot2112 said...ideal numbers for BLM's are 128 under all conditions, but this rarely happens.
The smoke could be valve guide seals, but on our cars the likely suspect is the turbo. If the turbo seals are old, you could be losing oil into the intercooler which will affect the max amount of boost you can run....plus any oil into the intake effectively lowers your octane.
You can still drive the car...when the turbo seals go all the way BAD there is no doubt....it will be a smoke show out the exhaust.
I wouldn't be hammering on it too hard until you fix the knock problem though.
John
What boost are you running?
Pump gas? What octane?
What chip is in it?
Stock injectors?
What other modifications do you have?
Like turbot2112 said...ideal numbers for BLM's are 128 under all conditions, but this rarely happens.
The smoke could be valve guide seals, but on our cars the likely suspect is the turbo. If the turbo seals are old, you could be losing oil into the intercooler which will affect the max amount of boost you can run....plus any oil into the intake effectively lowers your octane.
You can still drive the car...when the turbo seals go all the way BAD there is no doubt....it will be a smoke show out the exhaust.
I wouldn't be hammering on it too hard until you fix the knock problem though.
John
Well, The boost is about 17-18 psi under WOT the knock gets around 8 deg with 10 pounds of boost. I'm running pump gas with 93 octane. It has a jay carter 93 street chip in it. The injectors are 009's and it's suppose to have a high volume fuel pump installed. Other than a AFPR and no cat that's all it has. I do stay out of but around 5 pounds of boost I can see around 4-5+ deg's of knock and some times 2 deg with no boost just when I give it a little gas. Now if I'm loosing some oil out the turbo into the intercooler would this cause knock? Thanks, Jason
Hmmm....something's wrong...you shouldn't be seeing any knock retard at 5 psi boost.
One thing that's not quite right is your fuel pressure. You say under boost your getting "almost 60". The FP regulator should add 1 lb of FP for every lb of boost....so 46 psi + 17 = 63 psi.
You should be on the other side of 60 psi when running 17-18 psi.
You're close, so that may not be the problem. A fuel pump hot-wire kit may solve that. The hot-wire kit gives the fuel pump more voltage, which equates to better fuel pressure at WOT.
With KR at 5 psi I would suspect that something is knocking around and making the computer pull timing. (False Knock)
Whenever you have a knock retard problem, one of the easiest things to do is run the gas tank low (or drain it) and add some high octane race gas. Then if you still have knock...it's probably false knock..(something's loose)
An oily intercooler will definately affect performance, but I don't think it will cause problems at 5 psi boost. Unless it's VERY dirty. It might be time to pull out the intercooler and clean it out.
I would take another look at your fuel pressure under boost. Make sure you're getting 1 psi FP for every 1 psi of boost.
Here are some good references:
http://www.gnttype.org/maint/basics.html
http://www.geocities.com/rad87gn/tech/knocklist.html
One thing that's not quite right is your fuel pressure. You say under boost your getting "almost 60". The FP regulator should add 1 lb of FP for every lb of boost....so 46 psi + 17 = 63 psi.
You should be on the other side of 60 psi when running 17-18 psi.
You're close, so that may not be the problem. A fuel pump hot-wire kit may solve that. The hot-wire kit gives the fuel pump more voltage, which equates to better fuel pressure at WOT.
With KR at 5 psi I would suspect that something is knocking around and making the computer pull timing. (False Knock)
Whenever you have a knock retard problem, one of the easiest things to do is run the gas tank low (or drain it) and add some high octane race gas. Then if you still have knock...it's probably false knock..(something's loose)
An oily intercooler will definately affect performance, but I don't think it will cause problems at 5 psi boost. Unless it's VERY dirty. It might be time to pull out the intercooler and clean it out.
I would take another look at your fuel pressure under boost. Make sure you're getting 1 psi FP for every 1 psi of boost.
Here are some good references:
http://www.gnttype.org/maint/basics.html
http://www.geocities.com/rad87gn/tech/knocklist.html
