Alky boost lower on high hp car?

[tlturbo]

OK, I keep reading about everyone being able to run 22-24 lbs boost with no or very little knock. Is this on slightly modded cars or very modded cars? Is it possible that you can't run these boost levels on a 10 sec capable car?

Look at my sig. I can't seem to run over 19 lbs without getting 14 -17 degrees knock at 760 O2's. I have a dual nozzle SMC with pump speed maxed out. Maybe the engine is breathing more than the alky system can accomodate?

Just looking for some thoughts as to why I can't run 20-21 (I'd be happy) boost.

Terry

 

[Razor]

Well to answer your question.. first you have to address is the pump in your kit putting out correct pressure. And the size of nozzles being used.

Can you bog your motor with the alcohol, in other words when you crank the pump control, does the motor sound lazy when you let off after a pass. If your drowning the motor then you have sufficient pump speed/nozzles. Your throttle will feel like the motor doesnt want to rev for a couple seconds after you do a run. if this is not achievable, then look for my first suggestion of checking your pump output pressure and nozzle sizes.

The you have timing as an issue. But first you must have your system inspected for flow.

Example.. if the pumps pressure dropped to 45 PSI at pump speed 10, then quad nozzles may not get the job done.

On my car I run approx 6-8 ounces per pass. Mid 11 second car.

I'll start you here.

Julio

 

[tlturbo]

Razor,

thanks for the insight and ideas. Sorry I haven't answered sooner but I got this damn cold bug that everyone down here has and I haven't been up to much this week.

I guess my first queston back is could you please explain the part about checking for enough flow from the alky pump. You make a hard fun (how fast) and then as soon as you let off, try to get the car to start accelerating again (just normal or floor it again?) and see if it stumbles? Kind of like when you prime the alky pump while going real slow and the engine wants to stumble?

What will the guage on the SMC alky bottle tell me?
Should I just ask Steve for a couple bigger jets so I can dial the pump speed back a bit and then increase it as needed?

Back to you when I feel better.

Thanks - Terry

 

[Razor]

An easy way is get a fuel pressure guage with a long hose and run it to the winshield, You'll need some adapters to make it work, alky wont hurt the guage if used for a quick test. easiest may be unscrew the little guage, and run the hose from that port.

Now go make a run and look at the pressure on the guage. See what the pressure is at the 1000-1320 foot mark. Or top of third gear. Once you know your pressure, then we get the nozzle size being used and we can make adjustments.

You have a lot of mods on the car, its requirement will be probably higher than the norm. but without data.. what can I say

 

[2 SLOW]

I have gone 10's on pump gas and methanol (see sig below). I have been running methanol for about 10 years. My car weighs 3500 lbs with driver, PT54, GN-1 ported heads, lock-up, CAS V4, 212-212 Comp cam, 4.1 Stage I, thru 3 mufflers, 50lb MSD's.

My alky system is a Jay Carter that I modified thru the years. It is two stage with first on at 11psi and second at 15psi. I use a standard windshield washer pump you can get at any parts store for about $25. It is about 1/4th the size and pressure of a SMC pump so I doubt that is the problem unless the pump is really bad.

I started out with some of the same problems you have, so I have to ask a few questions.

first what chip are you using and what injectors. Is this someones "alky" chip? I found that my car likes a just plain street chip with 20* timing.

next what are you doing when you get all this retard. If it is from a start and you spin the tires it could be vibration from the spinning or the fact that you unloaded the motor or both. Mine will go 14* if I do that. Also sometimes the shifts can do it too. Testing for retard should be done at 60mph on up so that it doesn't downshift and you are testing at max load. Have it in third gear and leave it there for testing. I turn my knock sensor off when racing and I'm at 26lbs boost. I have tested at 60+ and get no retard, so I know what I get at start is false knock. When I turn it off I pick up .1 to .15 sec in quarter.

Obviously you have to be very sure you have everything sorted out before doing that. I'm just saying it can be done. I'll watch this thread and see if I can help. This may only be a start to try to fix your problem, so don't give up. And this could aslo have nothing to do with it, but I thought I'd take a shot at it. Good luck.

 

[Razor]

Dennis,

Welcome. I've heard your name mentioned.. glad you finally posted in this section.

I wanted to add, see here is where recording the run really pays handsomly. Like directscan, so you can see when the knock is occurring, at what speed, what timing when the kr occurred, injectors, O2's, etc.. and determine the cuase of the problem. One issue being insufficient alky, another being too much timing, mechanical conditions, etc..

 

[2 SLOW]

Razor,

Nice to meet you too. I got on the net about a month ago but have computer problems that would not let me post. Last night I got in for awhile, and later I left board and came back and couldn't post again. I'm at a friends house to reply tonight. This weekend I'm getting this fixed I hope.

Anyway I have looked at a lot of threads about alky like everyone does and see a lot of incorrect info, but your info is always correct so I hope it didn't look like I was in any way disputing anything. I was just trying to add to it.

I agree with everything above and recording full runs goes without saying, but in the past I had lots of problems in the first few hundred feet of the run and only suggest 60+ in addition to full runs to see what happens up at that speed. False knock is a tricky thing. If it is bad enough it retards so quickly the the motor can make noises that sound like detonation and fall on it s face, etc. Also most chips have a decay rate to bring you out of retard so that if you don't stay in it ( and who would) you won't know if it will run good at 60+. I hope I"m saying that right. But I expect there are a lot of other issues that should be checked before he gets to this point. May be getting ahead of myself here.

 

[Razor]

Dennis, no toes have been stepped on. I always welcome comments, critism, good, bad, etc.. many thanks for the thumbs up.

There is a lot of misinformation.. a lot of unknowns.. but its dialect like this that leads to solid ideas in combatting issues. And getting better understandings how things happen.

I've never unplugged my knock sensor.. Its about the only thing on my car I ever look at. And I guess this is where knock suppression chips like Reds, Eric, etc make .. for this bottom end knock issue.

The board once you have your user name and password, should be pretty seemless for posting and such. problem has been from my understanding getting that user name/password correctly activated.

Hope you get the puter issues resolved..