Tuning at the Track

[Twil]

Tuning question:

I am new at this Turbo – Timing – FP tuning thing. So far I’m doing ok, if U don’t count the Head Gasket I just blew last week at the track. I’m all fixed now (15+ hours !) but I did it myself.

Week one:
Alky not adjusted correctly – car fell on its face all but one run.
Best run 12.8 @ 106mph

Week two:
Alky working great on the street. 24# boost on 93-Oct.
Run #1 blown head gasket ! (No race fuel)
1.86 60ft

Week three:
Weather was great (low 70's -high 60's)
Alky setup is good. Turned down to 20# boost, removed 2 degree of timing, and add 2.5 gal of 112-Oct.
Run 1: 12.65 @ 107.67 1.96 60ft ( 20# boost - O2 750mV – 0.0 KR)
Run 2: 12.53 @ 110.49 2.00 60ft ( 22# boost – O2 714mV – 0.7KR)
Run 3: 12.23 @ 112.19 1.86 60ft ( 24# boost – O2 703mV – 7.5KR) New Personal Best !!!

My boost seems to go about .5# higher for one or two frames per run – I will assume this is normal.
My tank was ½ full of 93-Oct and then I added 2.5 gal of 112-Oct. (Didn’t help much – too much 93!)

Only changes made where boost. I just realized that I needed to increase FP also. Is this correct. I am showing 70PSI of FP on my Auto Meter FP gauge at WOT.

BLMs and INTs are at 128 for entire WOT run. (doesn’t this mean the FP is ok ??)
LV8 (Load) = 254 at WOT
TPS = 4.92 – 4.96 this seem a tad bit high.

Any help to get me into the 11’s. I want to run safe 1st, so I will tune to get there – not adding more parts.

Do I need more Octane or fuel pressure, or what should I do next?

 

[azgn]

you need more octane....7.5* of knock retard will take out another gasket....prolly lucky it didn't go on that fastest run.....do not be surprised if you lose another gasket soon (they usually don't blow when initially hurt.....they go out sometime later)

tune for 0 "ZERO" knock running as much boost as you are

you are about maxxed as far as fuel pressure is concerned...Walbros start to get inefficient around 70 psi unless you have a volt booster....with more octane, you should turn the fuel pressure down

start at 20 psi(boost) or less and tune for lowest fuel pressure without knock and work your way up s l o w l y on the boost & pressure

your combo should be good for 11.7 or so on race gas (110 or better) and about 25 lbs boost with decent 60' times (low 1.7)

good luck!

 

[peterkin]

don't those 02's scare the he\\ out of you or is it just me?

 

[azgn]

well, the 02's are low, but it is the knock retard that scares me!

Get rid of that, and the 02's should be fine...I would rather tune out the knock and then look at the 02's......something in the 750-800 range usually works on race gas

 

[Twil]

Knock Retard

I thought that a small amount of knock (2-5 degrees) was normal - per the Turbo Link manual. More than 10 degrees for more than a few seconds is bad (lift throttle).

Brandon

 

[UNGN]

Re: Knock Retard

Originally posted by Twil
I thought that a small amount of knock (2-5 degrees) was normal - per the Turbo Link manual. More than 10 degrees for more than a few seconds is bad (lift throttle).

Brandon

You really want to tune for no knock. Do this by adding octane and not FP. 2-5 is OK when you are running 18 psi, but at 24 psi and running Injectors on the edge, strive for none. At least that is what I do, and I've never blown a headgasket in 7 years of racing my TR.

You are on track to run pretty easy 11.7's, but you'll need 28" tires like 275/60's to run consistantly faster than 113 or so.

 

[Twil]

Sorry,

This is what is listed in the Turbo Link Manual:

0 - 1 degree KR most runs
2 - 3 degree KR optimal
7 - 9 U should never see

O2 volts should read .769 - .780V @ WOT
Brandon

 

[blackbuick87]

Originally posted by Twil
Sorry,

This is what is listed in the Turbo Link Manual:

0 - 1 degree KR most runs
2 - 3 degree KR optimal
7 - 9 U should never see

O2 volts should read .769 - .780V @ WOT
Brandon

As is stated above, thats fine at 18psi, but at 24-25psi tune for ZERO KNOCK

 

[TT/Ameasap]

It all depends on how much of a hurry you are to rebuild your motor!

Tune with 0.0-0.9 KR and you know your motor is not getting damaged But, if you go the other route with just get it to the elevens attitude, you will be replacing head gaskets AGAIN!

Remember, harsh detination occurs at high boost levels and in 3rd gear Does your manual tell you that!

 

[Twil]

Good Point !!

I will be more conservative - I should have realized this when I blew my HG last week !!!

Thanks,
Brandon

 

[Weazel]

Hey Twil, don't feel bad, that's how ya learn, by breakin' stuff
It's been said on this board that up to 4 deg is okay, but that's definitely NOT at those boost levels. I would agree, tune for 0 (easier for me to say than for somebody to DO though). Your car sounds like it has a ton of potential. Take your time, 11s will come sooner or later. Good luck!!

PS I'm planning on alky later in the year, so I'll keep you in mind when I run into the same problems inevitably!

 

[V6POWER]

We have similar combos. I tune for zero knock at 23-24# boost with 93 octane + alcohol. So far I have not blown a head gasket with over 200 strip runs. See sig. for combo/time.

 

[Twil]

Look Quick,

Did U run that time (11 sec.) on Alky only or did U add some race Fuel??

Brandon

 

[ijames]

As others have said, on high boost you want zero knock. You really need more fuel to get those O2's up a bunch or you may hurt the motor even with no knock (your egt has got to be sky high that lean). You are already pushing the fuel pressure up some (with 70 psi at 24 psi boost you have 46 psi base pressure) but depending on your fuel pump you should be able to go up some more. Just watch at wot and see if the fuel pressure goes up there after you increase it. The INT is held at 128 at wot, and lots of chips lock the blm at wot at 128 at wot so it's up to you to vary the fuel pressure to get the O2's right (that's why they lock the blm, so you CAN tune). LV8 should be 255; I don't know why it stayed at 254 but I don't think it's a big deal. The ecm is supposed to set a code if it sees the TPS over 4.90 V for several seconds but some don't. You should lower it a tad because if it does set the code it will also default to a tps of about 2.5 V and you will go lean. In most chips, including the stock one, anything over 4.2 V or so won't change anything.

 

[V6POWER]

Ran that on 93 + 50% denatured/50% distilled water.