so i got a 03 Z built DE, greddy tt (18g).....i have about 40K miles on my build 17psi of boost and was running great no problems. So the other day i decided to go and get a race gas tune.........so i go put it on the dyno put some C118 in the tank. We started with very very conservative timing and had the A/F about 10.9......well, the first really pull we did was at 22psi and as soon as it got to 5000rpm it started shooting coolant out of the overflo tank. We immedately shut it down and just let the car idle. As soon as the tuner took his foot off the gas the coolant stopped coming out. The car never ran hot, no coolant in the oil or coming out of the exhaust and the heater still worked. We unstrapped it from the dyno and i went and drove around alittle and then drove it to work. The car ran great it even idled better than what it did before i put it on the dyno.

(Back Story).........a couple of days before i replaced the D.S. valve cover and had to disconnect one of the heater core hoses and it stayed disconnected for about 2 days. I purged it afterwards but not as long as i usually do but it seemed ok but i didn't drive it i took it straight to the dyno.



(Onward)............So i get the car to work and decided to purge the coolant system. It had alot of air in it, i mean it took hours and i didn't think i got it all out by the time i had to leave. On the way home i decided to do a couple of short low boost(10psi) pulls just to see how the car would react. It ran perfect. So the next day i drove it to work again and purge it again to make sure that i got all the air out. There was still quite abit of air in it but i got i would say 95% of it out so i decided to do a high boost (17psi) pull. Well, we forgot to adjust the boost controller back and when i got on it, it got up to about 19psi before i got off the gas. I only got up to about 5k rpm when i realized how much boost i was at before i let off. and that was on 93 pump gas. Well i get out of the car and pop the hood and it wasn't shooting out coolant but it had filled up the overflo bottle (it was about half full before i started the runs). the car was still not overheating and running great. I drove it home and let it sit for about 3hrs and the overflo is back to just above half full. I checked the oil its fine no coolant, no coolant coming out of the exhaust, no coolant sweating out of the heads where it meets the block everything is dry and the heater still works (very hot).

so what do you guys think?..............did i lift the heads or did i just have really bad air pockets?

-dave

 

Who is your tuner and what did he have to say about it?

 

I had that problem with my car, it had a real bad air pocket. These cars are kinda hard to get all the air out. I was only running on a stock block though so I have no real experience with that high of boost.

 

^ +1 on who is ur tuner?

 

what head studs are you using? oem, arp ? L19s??

 

Sounds like what I experienced with head lift when I had it. Mine would hold 10psi, anything past that it would peak like normal, then boost would taper off slowly as the coolant shot out onto my windshield.

Good times.

Get yourself a spill funnel for purging air, and be done with it. If afterwords this happens you may have a serious issue.

 

If you constantly have air in your cooling system, specially after doing a couple of runs, then it sounds like your head gasket might be leaking while your in boost. I had this issue for about 2 years on my VQ30, like Alberto, anything above 10psi it would leak cylinder combustion pressure into the cooling passage and overpressurize the cooling system, forcing the overfill tank to get filled. I dealt with this for that long, put a higher pressure radiator cap, blew up a good amount of radiator hoses, till eventually I replaced the head gasket and didnt have an issue after that. I still have my aluminum radiator I used to use, it actually expanded on the sides from so much pressure in the cooling system.

What head bolts do you have?

 

Need some info on parts you have installed and who built and tuned it.

But sounds like headlift.

Tom

 

+1
Give us the mod list rundown.

 

well guys i purged it again today and hardly no air came out. After work i did 2 10psi (car ran great), 1 12psi pull, 1 14psi pull, 2 17psi pulls all in about 20mins. Every pull the car ran great, boost held strong, car pulled hard. Before i started i checked the overflo bottle and is was 1/2 full, after all of those pulls it was just above 3/4. No boiling coolant in the overflo, never overheated or anything. All pulls were done in 3rd gear up to 6250 rpms (i was running out of road). So i will say this that if it turns out to be just a big air pocket and the car is fine i don't think i have the ***** to put it back on the dyno and try it again!

 

oh i have L17 headstuds, stock heads and cams, cometic head gaskets, Utec, and 750cc injectors. National Speed has tuned the car ever since its been built back in 07,08. But the car wasn't built by National Speed

 

That sounds like a horrible problem to have!

 

/\/\/\ always possible that it was just air....these cars can be a bear to purge all the coolant out off.

Like Alberto said get the proper funnel setup and you won't have this problem anymore

Tom

 

^ I hope so.....i let the car sit today and i drove my other vehicle but the coolant level in the overflo is at just above a quarter

 

honestly didnt read ur post carefully, i will later, trying off my phone..binder has similar symptoms because of headgasket didnt he?

 

so question............after i test the car few more times and if it runs like it suppose to, should i go and put it back on the dyno for 1 pull on high boost(17psi) just to check and make sure the a/f's, boost and the powercurve is spot on?...........or is that just overkill

 

i had similar problems with a blown head gasket except my coolant levels in the res never went down.

If there is air being forced into the system from blown head gasket or head lift then the coolant bottle will fill and never go down once cooled. If it goes down then chances are the system is still sealed and it's operating normally.

L17's are the standard studs right? Those might be lifting with cometic gaskets and that much boost. I'm not sure, i use L19's and i think everyone else with high boost runs L19's.

You mght be stuck with lower boost until you run better head studs for more clamping force.

 

If I have a problem arise, I know who I should ask. The optimistic people! Some of u guys here give it too straight and that would just make me sad

 

the truth hurts but it's the truth, you can't hide it. once you log off the forums reality will always be there.

 

well today i took the car out for another set of test pulls. i did one run at 10psi and then three more at 17psi and the car ran great afterwards i checked the overflo and it rose alittle bit more than a 1/4 and after the car cooled down it went back down to where it was. So i tell ya i really think it was just a air pocket because the car is running to good and i would think that after all of these pulls then the headlift would be clear!