Track Times

[lordmikef]

Went to Island Raceway today and took my 87 GN out for the first time with the engine rebuilt and the ta-49 on. First pass, I went a 14.0 with a 2.2 60 foot and 15 pounds of boost. Second run was a 13.5 and ad 2.0 60 foot at the same boost. The third run, I put the boost up to 17, and spun the tires a little bit off the line but still managed to go a 13.3 with a 2.0 sixty foot at 102 mph.

Mods are as follows. .20 block with diamond pistons, polished and ported heads with new valves and springs, ta-49, nitto 555r, 42.5 pound injectors, armstrong 340 fuel pump, rear air bags, and adjustable fuel pressure regulator. Bags were at 5 in right and 20 in left. Tired were at 13 each and fuel pressure was at 41 line on.

I would think this combo would be good for at least low elevens. Any help would be great. Having some trouble gettin the nitto's to stick. The track sucked, but i still expected a little more out of the car. It spun when i left the line with about 6 pounds of boost. It was ok at about 2 pounds off the line. Thanks for the help.

 

[turbot2496]

We need more data...

Using scanmaster or direct scan??

What fuel??

Stock intercooler??

What chip??

Your 60's are costing you at least .5 sec and your mph is low. You also need to run as much boost as you can. Sounds like you've got some tuning to do to get into the elevens. You knocked .7 sec off from your first run to your last so thats a good start.

 

[2QUIK6]

You won't see 11's unless the boost is cranked up to about 24-25#. Were you running pump gas, is that why you never cranked to boost up any higher than 17?
Going to need C116 fuel to get past that and then probably alot more timing. What timing are you running. A TA-49 with ported heads will be hard pressed to see low 11's unless you have some very good tuning skills, I take it you do have a scan tool?
Mid 11's would be a more obtainable possibility.

 

[lordmikef]

the timing is 25 and im running 93 octane. i can get it up to 21 pounds but im afraid of blowing another head gasket. What can i do to prevent that from happening while i keep the boost high? I'm trying to go as fast as a can without race gas. i run a computech system in the car but im gettin the scan master. If the motor will allow 22 pounds, is there any way to keep the head gasket on without alcohol or race gas?

 

[lordmikef]

i have the stock intercooler and i run an adjustable chip i got from jay's buick parts. it sets the timing at 25 and the boost where i have it

 

[turbot2496]

hmmmm.... OK well alot of your problem is apparent now.

You need to be running race gas... especially if your afraid of blowing head gaskets. Your running 93 now and with a good 60ft the car would be in the 12's and thats about right.

Now with some good fuel you could crank that boost up and shoot for the moon.

Get a knock detector or scanmaster so you can monitor your Knock retard and o2's. You must have one of these.

25 degrees of timing on 93 octane seems like an awful lot... I would dial that back to about 19 for the saftys sake and start there. I know nothing about Jays adjustable chip but thats alot of timing for 93.

Stock intercooler will hold you back a little too. You'll probably need at least the Dut neck mod to get close to your goals.

 

[lordmikef]

thanx for the help

im getting a little wheel hop now and then off the line. i was hoping the air bags would take care of that. They are set at 5 on the left and 20 on the right. is there a better place for them?

 

[lordmikef]

why is it that i would be able to run more boost with the race gas?

 

[TurboJim]

STart at 20psi on the Nittos and go from there

 

[pacecarta]

boost adds heat , approx 10 degrees per pound of boost, that heat increases the likely hood of detonation
the stock ic will drop temps about 100degrees
if its 60 degrees out and you run 17lbs thats 230 degrees before I/C , and 130deg into the intake , its like driving on a really hot summer day and knock will occur with pump gas
without a effecient way of dropping that heat (intercooler or alky injection ) that incoming charge air temp will be high and with 93 (if it really is 93 they pumped in your tank that day) will cause detonation (knock) and you will get knock retard and risk engine damage
race gas basically has an increased octane level which will retard detonation and allow more boost and timing .
if your intercooler were made more efficeint the temp would be lower because the compressor could make the same 17lbs manifold boost at less pressure at the compressor (stock Intercooler costs you about 5 lbs of boost so for 17lbs at the manifold (your boost gauge) you need about 22lbs at the turbo side .

if you monitor your knock it may be possible you could crank in more boost untill knock happens but i would say youve past that point already on 93 ,
once your at the boost limit for your fuel , if your timing or air temps change (cool now but when it warms up so does the charge air temp) would affect what you can run safely without knock .
17 is really low boost for a TA 49 and not near its potential ,Im running alky inj and run 21-22lbs on a stock turbo and I/C and plan to go to 26 -27 with my TA49 ,dont try this on 93 alone !!

C16 will allow you to add more boost but will quickly foul your stock O2 sensor and kill a catalytic converter if you connect it without draining the tank , but if your looking to put up low times at the track it will do that .
you could try 100Unleaded and that should give you ability to run a respectable boost level without knock without the worry of fouling your O2 sensor or damaging your cat converter once you bolt it back on for the street.
on the air bags you may want to try a little less , like 9-11 on right 5-6 on left to allow for some squish of the rear end.

 

[2QUIK6]

If you have been running more than 20 degrees timing and more than 17# of boost with only pump gas for very long, you're going to need much more than head gaskets....probably all your rod/crank bearings are shot too.
This is the reason for using high octane race fuel or alky injection.

 

[lordmikef]

i undestand the concept of high octane reducing knock, but i have the felpro gasket in there and i was wondering how much abuse in terms of pounds that the gasket can take

 

[turbot2496]

???? Hmmmm .... Well Mike... I don't think your getting whats being said. Your asking how much abuse your Fel-pro gaskets can take??? Who knows?? But we can tell you that if your engine is detonating its not good so why not tune for 0 knock retard. Alcohol injection, race gas, better intercooling etc etc will allow you to run more boost without KR therefore making more power safely. If you want to run 93 with the stock intercooler and no alcky injection or race gas, then a mid to high 12 sec 1/4 is the most you can safely hope from your combo and you must get a lower timing chip or your gonna break something.

 

[pacecarta]

the way i understand it the gasket isnt the determining factor for boost , 30lbs on top of your 145-150 base isnt much
the combustion process creates more stress than the turbo and static compression , a timed burn when the fuel air mix is ignited by the plug just before the piston reaches the top and maxes as the piston is on the downstroke isnt damaging or abuse , a combustion which ocurrs too early on the piston upstroke (detonation) creates much more stress , its this violent detonation which bounces(shocks) the head off the gasket and eventually leads to damage not just to gaskets but pistons , rods and bearings ,
leaning out is the other half of the equation and it will burn its way out the path of least restistance , detonate while lean and it will burn through the head gasket , the piston or the valves

 

[lordmikef]

im just trying to get as much input as possible because i really dont want to have to rebuild this thing again bear with me

 

[XLR8]

Originally posted by lordmikef
the timing is 25 and im running 93 octane. i can get it up to 21 pounds but im afraid of blowing another head gasket.

Do you have a scan tool? If not GET ONE!! at 25* of timing and boost from 17# - 21# I am betting you are having a lot of knock retard. Knock retard - in addition to slowing you down - can take out another head gasket or do much worse damage. A scan tool will also let you tune the car to an extent by adjusting fuel pressure and boost.

Get a scan tool, use race gas and high boost and with a good launch on your Nittos (1.8 60') low 12's are there for the taking. For 11's you really need to get your car dialed in and get your 60' times in the 1.6 range.

 

[lordmikef]

thats another problem i was having. i couldn't get the nitto's to hook. Granted, island dragway isn't the best track, but the first pass i left at about 2000 with no boost and a 2.2 60 foot. no problems. the second pass, i left at about 2 pounds and had a 2.0 60 foot and the third pass, i brought it up to about 6 pounds and shook the tires any advice?

 

[pacecarta]

like jim said "STart at 20psi on the Nittos and go from there" .
he meant air pressure in the tires , 13pounds is low and you may not have a good flat contact patch , do yourself a favor , before you thrash your car again get(or borrow) something to monitor knock like a scanmaster before you hurt something , no one likes doing gaskets and no one here want to see you have problems
I would expect much better 60s from nittos , i pulled a 2.006 on my street tires , goodyear 235 55 /16 at 35 lbs , these are the tires gm put stock on the 4th gen camaros (mine were used and came from a wrecked z28 in the salvage yard )

 

[TurboShane]

25* of timming on 93 octane, you must be out of your mind. Your going to to blow that thing up in short order. You must be pinging the hell out of it. That's why you MPH is so slow.

 

[lordmikef]

i have a knock sensor in the car and had no ping