Reducing Knock

[BlackMetal]

My Scanmaster readings are starting to worry me. I was racing (and losing to) a Charger SRT-8 on the way home, and my reading got up to 15 when I really stepped on it.

Before I start talking about fixing the knock, I have a question. I was reading an older thread about knock where someone replied and told the thread starter that if their car had knocked hard enough to get a 9.4 on the Scanmaster, they would have heard the knock themselves. Is this true? Of course, I was going down the highway, windows up, heat on, so maybe I wouldn't have heard it anyway.

Anyways, I wanted to accomplish two things with this thread. (a) Get opinions on a list I have so far of things to remedy the problem and (b) get more suggestions that I haven't thought of yet. Here's what I have in mind so far...

-Spark Plugs: New plugs in general if they're fouled, but maybe one step colder
-FMIC: Reduce charge air temp, keep combustion temps down
-Fuel System: Cleaning/new filter, 42lb injectors, adjustable regulator, hot wire pump or upgrade to new pump
-Boost Controller: Figure out where it starts knocking, and keep my boost lower

That's about my only ideas so far. I wanted to save up for 17in wheels, but I want to know my car is healthy first. It'd be nice to lay into the throttle and not see knock register on the scanmaster. I appreciate any help.

 

[pacecarta]

http://www.gnttype.org/maint/basics.html

 

[mikec1969]

I believe you would hear it knock @ 9.4. Be sure your exhaust is not touching the frame it can cause false knock readings. My limited experience with Gn's tells me they tend to knock in the gear changes and remember the air is cold and dense which can make it knock worse yet.

 

[BlackMetal]

I believe you would hear it knock @ 9.4. Be sure your exhaust is not touching the frame it can cause false knock readings. My limited experience with Gn's tells me they tend to knock in the gear changes and remember the air is cold and dense which can make it knock worse yet.

Well I understand that if I got a frontmount I'd actually be cramming more air into the cylinder, but I thought the drop in temperature would stop it from detonating. I guess I'll start with the simple stuff like spark plugs and fuel system.

 

[blackstallion]

what chip are you using?How much boost are you currently running?What grade octane are you using?Check fuel pressure?Give us some more info.

Make sure you have and upgraded pump,and hot wired.
New fuel filter
Get a chip thats compatable with the boost level you are running and the grade of gas you run.
My experience with these cars if u have a relatively stock combo ie 3inch dp,stock turbo,exhuast ect.On pump gas/no alchy you are very limited in power trying to max it out or even come close to it is almost impossible without getting knock of course this assumes you car is in good running condition.I would suggest you get alchy injection,or get a denso lead proof sensor and run race gas.

 

[BlackMetal]

what chip are you using?How much boost are you currently running?What grade octane are you using?Check fuel pressure?Give us some more info.

Make sure you have and upgraded pump,and hot wired.
New fuel filter
Get a chip thats compatable with the boost level you are running and the grade of gas you run.
My experience with these cars if u have a relatively stock combo ie 3inch dp,stock turbo,exhuast ect.On pump gas/no alchy you are very limited in power trying to max it out or even come close to it is almost impossible without getting knock of course this assumes you car is in good running condition.I would suggest you get alchy injection,or get a denso lead proof sensor and run race gas.

No chip installed. Not sure how much boost I'm running because I only have the stock boost gauge, but I can max it out easily. Around Chicago I buy 93 octane.

I'll look into alky.

 

[tford]

I was the one that started the thread about the 9.4 degrees of knock but I have the single shot 3" exhaust so I couldn't hear it anyway.

 

[Ormand]

No chip installed

The engine will run, maybe, with no chip installed, but it wouldn't run very well! If you mean you still have the stock chip, that is probably a big part of the problem. Stock chip, stock fuel system, todays fuel, not a good combination.

 

[scot w.]

first thing

No chip installed. Not sure how much boost I'm running because I only have the stock boost gauge, but I can max it out easily. Around Chicago I buy 93 octane.

I'll look into alky.

The VERY FIRST things you should do is to get a 30/30lb boost/vac gauge, EGTgauge,fuel press gauge and a FUEL PUMP,filter and a adjustable fuel regulator. If you don't your going to ruin your motor getting into boost. getting the boost/vac gauge is good for more accurate readings and also seeing you got good vacume. EGT gauge is also good to see what temps your getting up to at WOT, I don't like to see it go over 1500deg.myself. The FUEL PUMP is the Most important part for you right now. We as T/R owners need to KNOW for sure that we are getting enough fuel ( VERY IMPORTANT). The fuel regulator so you can adjust the fuel. like for what the chip designer recomends. You should not get alky untill your car is 100% running correctly and you know it inside and out on what it likes.(how it acts ). I would highly recomend Eric Marshall at Turbotweek. and tell him what your running for gas, turbo, injectors. mine from him, the timing was 21/18deg this was to be on the safe side and the chip made my car run 10 times better at idle and WOT. good luck and if you ever need anymore answers were here to do it for ya.. Scot w.

 

[Rodney87GN]

I'll look into alky.

I'd hold off on the alky til you figure out why it's knocking. You should be able to run 16-17 psi on 93 octane with very little or no knock at all. Even Razor will tell you to make sure everything's in good order before adding alky and turning up the boost. But yeah, get a real boost gage first!

 

[Tampa T-Type]

First things first

Seems money is an issue so start with the basic tools you need. Get your boost gauge to show both vacume and boost 30/30. Tweek or the Extender chip, fuel pump Welbro 340 and hot wire kit and fuel pressur Reg. This will give you a good base line. If you keep on knocking that motor you will be towing it home.

 

[Blazer406]

As others have said... and I will say.... do the basics first..... run through the spring cleaning list over at gnttype.org. A chip set up for 93 like Eric's TurboTweak chip works great. IT gives some tuning options for timing and fuel as well.

Others have mentioned running 16+ psi on pump gas..... I guess I was not doing it right with the stock chip....and everything else stock..... I could only get about 13 maybe 14 before I had enough knock that I was uneasy. I believe everyones car is a little different. Get the simple stuff sorted out... and running right.... then you can get the alky and run 23+ psi with the stock turbo... and probably 30 psi with a bigger turbo on a stock longblocked engine. It is a whole different world above 20 psi. :biggrin:

 

[BlackMetal]

Thanks for all the replies. I guess I'll upgrade my fuel system but I really don't see the need when my car ran extremely rich on the dyno.

Today at work I grabbed some fuel system cleaner and a new filter, so I'm going to do that this weekend as well as change the sparkplugs.

I'll probably end up getting the pump/hotwire kit from Racetronix, but like I said...I think a lot of people go overkill with these aftermarket fuel pumps. I've had people suggest fixing this problem with 60lb injectors for a car running 245hp.

What kind of mod information do you have to provide the vendor for these 93 octane chips? If they account for injectors and things like that, then obviously I'm going to wait until all my mods are done.

 

[scot w.]

Thanks for all the replies. I guess I'll upgrade my fuel system but I really don't see the need when my car ran extremely rich on the dyno.

Today at work I grabbed some fuel system cleaner and a new filter, so I'm going to do that this weekend as well as change the sparkplugs.

I'll probably end up getting the pump/hotwire kit from Racetronix, but like I said...I think a lot of people go overkill with these aftermarket fuel pumps. I've had people suggest fixing this problem with 60lb injectors for a car running 245hp.

What kind of mod information do you have to provide the vendor for these 93 octane chips? If they account for injectors and things like that, then obviously I'm going to wait until all my mods are done.

The reason to upgrade the fuel pump IS, for ONE you don't know how old it is! TWO you don't know if it's still stock,then your probly dropping in fuel pressure at WOT. Mine did it! thats why you need the gauges too. and I replaced it with the red armstrong XP pump,a/c delco filter and 60lb inj. You should listen to us we have all been there and if you don't start with the fuel, your going to WRECK something. When I bought mine it ran rich too, when I got to looking at it, the fuel pressure was set at over 60lbs,vac line off, with stock injectors "BAD"!!! when I installed the fuel press gauge and went WOT the pressure DROPPED!! NOT GOOD! so I replaced it and never looked back. with the red armstrong XP pump and 60lb injectors you will be good well into the 11's maybe 10's...

 

[BlackMetal]

Alright I'm going to order the Racetronix kit with a pump and hotwire kit and an adjustable regulator.

 

[VandaLL]

were you able to fix the knock problem with fuel system upgrades?