my head hurts. detonation. need tuning help

[davekusa]

You’re going to see this post on more than one forum. I’m trying to get a lot of input on my issue.

351W o-ringed block/receiver groves and copper gaskets. FAST DFI sequential with WB02
Non intercooler supercharged.

I had my car tuned in spring and I lifted a head gasket on the dyno. I didn’t realize why this happened until recently (detonation). I resealed and retorqued the gaskets. Down at the track a few weeks ago I melted a piston (injector concern). So I took my engine apart an I see lots of evidence of detonation.

Timing is at 19 deg. A/F is 11.2 at the top of the table. 112 octane. IAT is 210-240F

Is my timing table off?

Are my plugs too hot?

Do I need to add alcohol injection or nitrous?

So far what I have decided to do for sure is slow the blower down to decrease boost and put new injectors in. Once I get this tune under control I’ll start adding boost.

Any input would be appreciated.

 

[turbov6joe]

The last thing I would throw at this mess is NOS! Try injecting Methanol and watch the detonation go away provided the rest of the tune is correct. I have no idea what heat range of plugs you need to run, but you might also try 1 heat range cooler and see what happens??? You also need to list specifics like compression ratio etc...

 

[davekusa]

8.5:1 compression

 

[Razor]

IAT is 210-240F

Answered your own question.

Just becuase its fat doesnt mean you cant detonate it. But when temps go up... watch out. And on the dyno your pull only lasts a few seconds.. at the track.. way way different.

Get the injectors flowed so they are matched, watch your plugs for any signs of detonation. Get those IAT's down... else you'll be in trouble again.

HTH

 

[davekusa]

I agree with you razor 100%. I guess I just didn't know if 2 more degrees of retard will take care of things.

I also read that you make a methanol/alky injection kit. Can that be used with nitrous?

 

[Razor]

I agree with you razor 100%. I guess I just didn't know if 2 more degrees of retard will take care of things.

I also read that you make a methanol/alky injection kit. Can that be used with nitrous?

The nitrous stuff is still in experimental. The current way its being done is with a separate pump.. tho this may change pretty soon.

So has it been done? Yes. There was a post from two months ago on an LS1 Vette that made 970 RWHP. It got 200 to the wheels.

Do I feel it still needs a little attention/thought? Yes. I'll be working on this with the new motor.. until then...

HTH

 

[bruce]

FAST DFI sequential with WB02
Non intercooler supercharged.

Timing is at 19 deg. A/F is 11.2 at the top of the table. 112 octane. IAT is 210-240F

Is my timing table off?
Are my plugs too hot?
Do I need to add alcohol injection or nitrous?

With MATs that high, you're in trouble.
IMO, lots of trouble.

Backing the timing down, and lowering the boost are a couple alternatives. But, all you'll be doing is trying to bandaid the real problem.

Adding an alky kit might be your best answer. But, with those high of temps., personally, I'd go with an intercooler, and alky.

Getting the timing table *correct* takes time, and alot of work. If all you're worried about is WOT, then life's pretty simple. BUT, you can build alot of unnecessary heat in the chambers, when it's wrong, and that can lead to detonation/ pre-ignition.

Yes, too hot of plug, or the wrong style will lead to detonation/ pre-ignition.

As mentioned, Nos is exactly the wrong thing you want to even consider.

 

[davekusa]

Thanks for the input. I had a smaller blower with nitrous on my old set up and it worked well. I still have the nitrous set-up with the new combo but have yet to try it.

I tried an intercooler but the plumbing was a nightmare and the massive size of it blocked too much of the radiator and caused overheating issues. So now I back to non intercooled.

Razor have you tried refrigerating the methanol/alky below zero?

 

[Razor]

Nitrous aggravates detonation. In other words if your motor is pinging.. and you spray it.. get the shovel out.

On the flip side.. alky controls the pinging.. so if its pinging.. you spray it.. it clears it rite up.

Typically I have had great results with alcohol applying heat to it.. not the other way around.. hard to freeze it here in Florida :biggrin:

The nitrous will... thats the big question that needs more R&D

HTH

 

[davekusa]

WOW. I find that very interesting.

 

[davekusa]

I would have thought that you would get the added benefit of cooling the intake charge even further.(refrigerated alcohol)

Razor, is there any way to hook up your kit to fast dfi or do I need to get your whole kit and hook it up as stand alone?

 

[Razor]

You need temp for the alky to flash.. nice thing is that turbo's do a good job of generating heat.

I run a FAST on my car, its VE tables are tuned with the alky spraying. So the controller sends a signal to drive a pump.. that introduces a fuel into the motor.. you turn down the injectors in your VE tables... badabing.. your target AF is reached.

The use the FAST to activate your nitrous system thats been supplemented by the methanol.... hehe :biggrin:

 

[davekusa]

I guess the question is without an intercooler at 240 intake temp chilled alky might still be hot enough to flash?

Do you sell your setup without the controller? I might have to give it a try.
This sound more and more like what my car is itching for.

 

[ijames]

The specific heat of methanol is 2.37 joule/(gram deg C) while the heat of evaporation is 1189.5 joule/(gram deg C), so the heat absorbed while evaporating is equal to the heat needed to warm the liquid up 502 deg C (if that were possible). Bottom line is that chilling the methanol will have a very tiny effect on the total charge cooling because the cooling mostly comes from the evaporation, not from warming up the liquid. For water it's 4.18 joule/(gram deg C) and 2258 joule/(gram deg C), an even bigger ratio.

 

[Razor]

I guess the question is without an intercooler at 240 intake temp chilled alky might still be hot enough to flash?

Do you sell your setup without the controller? I might have to give it a try.
This sound more and more like what my car is itching for.

No.. anything above 60 degree's will do just that.

The alky will drop temps at least 100 degree's. No need to chill it.

As to sales and such, contact me off list as I try and keep business and technical separate.

HTH