Ok so i got my car running. She's a sebring 420a with HRC stage 3..she's doing fine except that when i REALLY hit her hard and get close to 10psi, the temp rises from right in the middle to about 3/4 to the top..and drops back down when i let off the boost...

When i shut off the car, i do not get the bubbling through the overflow tank like it does when you have a gasket leak.

My heater also works which tells you that a coolant passage is not blocked off.

What i'm concluding is that i need to run a cooler thermostat temp? right now its at the stock w hich is i belive 180 or so...i have heard Armond running 160 on his stage V..

Anyone have any ideas?

Thanks for the help...

Boost rules!

If you run an FMIC, it could be the heat it is passing to the air is soaking your radiator. If you think this is possible, look at the Fluidine.

As for running a cooler thermostat, i hear it will make you run rich. The ECU won't see the coolant temps it expects, and gives more fuel in an attempt to warm the system up. Since the thermostat is already open, the system will never warm up, and you just end up running rich. Armond runs an Accell DFI, which likely gives him an edge on compensating for that.

I don't know much about your setup, Kiku. Is there somewhere i can read over your mods list? You have a page on ASOG?

You said that when your coolant bubbles into the reservoir tank it means you have a gasket leak? Which gasket? Mine used to bubble sometimes before I got the turbo. I havent noticed it since I have been turboed though.

I have the 420a with 10:1 compression je pistons and crower rods bored over to 3.5" bores, and total seal rings. I have the hrc stage 2 with hrc fmic (which with the built up internals, makes this a stage 3 right?)

Anyways, i just got my cyl head rebuilt and put in a brand spankin new MLS head gasket. I use arp head studs, all torqued to 71 lbs and followed the torque sequence and specs from the service manual. Also used the specified mopar gasket sealant spray stuff.

I've had a copper head gasket before, and i had two types of problems: 1) heater would not work, engine would overheat = blocked off coolant passages
2) engine would overheat, and when you shut off engine, all coolant would bubble over to the overflow tank.

My current problem doesnt follow any of the patters above. Engine gones from right in the middle in the temp gauge to about 3/4 the way to the top. It will only happen when i hit gas for extended period of time. If i let off gas, it will tgo bakc to normal. If i then proceed to cool the turbo down and shut off the car, it will not bubble at all. Strange.

tomorrow i'm going to retorque the cyl head.

You are still stage 2 until you have larger injectors and fuel controller (the ability to run 15psi) but you are like bullet proof stage 2 I guess (stage 2+).
How long is an exteneded run (like what speed and gear do you get up to before temps rise)? Highway or street? I NEVER run hot on the street (stoplight to stop light WOT or just racing up to jail speed). The only time I run hotter is cruising on the highway not even in boost. It runs a little hotter than normal (enough to notice) and then comes back down to normal and constanly cycles between a little hotter than normal and normal. Mine cools down when I speed up so I guess its from the intercooler or a lazy water pump going slowly. The only time I run hot enough to granny it is with the AC on under boost on the highway (In which case I can nearly peg the H if I cont to get into boost and/or downshift).
Come to think of it I dont have a thermostat in right now. Wonder if putting one in will make things better or worse. Supposedly coolant doesn't stay in the radiator long enough to cool without a thermostat. I have no problem reaching operating temps though.

Check your bolts on your manifolds (intake and exhaust) and check your fuel pressure. How much lag do you have when you build 10psi?

I took it out again this morning..hit close enough to 10psi (about 7-9) and it didnt overheat at all. Usually was when i was going 1st/2nd/3rd gear and spooling up, but that was last night.

I'm going to try a lower temp thermostat and retorque my cyl head up to 75ft/lbs on the arp studs anyways.

I'll also recheck my exhaust and intake manifolds...

thanks, i'll let you guys know if i can find any more patters about this..

Also, I do not know if the spooling/lag time is normal for this turbo.....depending how Im pushing or starting the car off the line, the boost may not hit for 1-2 seconds or until 3k rpm or sometimes until 4k..its hard to explain...

does anyone know if our stock radiators are a one cell or two cell radiator? Just wondering because my brother picked up a 2 cell radiator for his turbo'd 200SX and the car is always cold. Point is he got it cheap through a radiator place and works perfectly without spending mad amounts of money on something like say the fluidyne.

A new radiator is not always the answer. Our radiator is sufficient assuming you are using an efficient fmic core that allows air flow. I have a stock radiator, ApexI FMIC, and 15-18psi daily with no overheating issues. The only time I had an overheating problem, which was EXACTLY like what Kiku is dealing with, was when my intake manifold was off.

Oh, on turbo lag, you should get 10psi around 2900-3100rpms. If not, you probably have a boost leak and need to do a pressure test.

hrm....yeah i think either my boost gauge is not hooked up right or i got a leak somewhere because i havent gotten to 10psi yet...closest i get is around 7psi and that's about when i run out of RPMs and have to shift..

Can you explain a bit more what an intake manifold being off has to do with overheating? sorry for asking but i dont see the point......

Kiku, you are bored 60 over? That is news I have just been informed of. I think you would be good to start with a thermostat and all those tricks in that case. Your block lost some of its cooling ability when you go that much over.

I would heat up the slights but durring high boost, runs... So I bought a Fluidyne and never again.... Also use water wetter, it drops temps around 20 deg on average. Flush your whole coolant system, run some super flush in it for 4 hrs, then flush it real good and refill... it'll get rid of any mineral deposits or other clogs and optimize the flow of your stock setup.

MuRiX's manifold was being held on by 2 brackets and one nut :). IT has MAD leakage between the manifold and the head, so hsi turbo would work EXTRA hard just to make 5 psi. all that spinning made the turbo extremely hot, and in turn made the entire engine compartment hot, and made the radiator VERY inefficient. that caused his coolant temps to go up, and power to go down.

bring it on............

hehehe ouch =)

I can vouch that my manifolds are in place because i just got my cylinder head reconditioned/rebuilt and replaced the head gasket and i tightened the intake/exhaust manifold with grade 8 studs so those mofo's aint coming off!!!

My car is not overheating anymore (maybe because its hyper cold out??) so I'm going to keep an eye out but still get the lower temp thermo...

Thanks guys. And yes i'm 60 overbore...

Amazingly, my car made 18psi in this condition. It was producing serious heat which I suspect is what killed my turbo seal. The car was performing liek you described, which is also why I asked about lag as that is a major syptom. We dynoed it like that before realizing the problem and it made 232@18psi. :( That was when I was in Texas having a very bad month with things breaking. It feels MUCH stronger now.

>I have the 420a with 10:1 compression je pistons and crower
>rods bored over to 3.5" bores, and total seal rings. I have
>the hrc stage 2 with hrc fmic (which with the built up
>internals, makes this a stage 3 right?)

I can't believe that you have 10:1 compression and are running turbo! Everybody I've heard of lowers compression when they add internals. Aren't you scared of detonating when you up the boost? I guess its safe at 9 psi...but, aren't you planning on running 15+ psi later? That just sounds dangerous. I'm just curious why you've chosen this route (seems dangerous).

Corbin

'95 ESI-T
HRC+FMIC+ETC...

Stan runs 10.5:1 and 10PSI, no problems other than (in his words) his POS car.

OK...I guess if he stays at 10 psi. I would really worry if he went to 15 psi. I plan on doing something like 9.0:1. I wanna be able to boost alot, but not lose too much off-boost power. Hopefully I can start building a second engine/trans in a year or less.


Corbin

'95 ESI-T
HRC+FMIC+ETC...

the reason being why i'm at at 10:1 compression is that i first started off my first engine rebuilt as a nos/NA kind of guy. I got the beefy crower rods, je 10:1 Pistons, and everything else you could name (arp studs/bolts/blah blah blah).

I then feel into the dark side (boost!) and love it. I am right now just going to stick to 10psi as its way more power than i've ever though of. I have not run into any detonation with 10psi and plan on going to 15 psi. Can anyone ever say for a fact that higher compression and boost will cause you detonation in our engines? our cylinder heads are really really well designed to prevent detonation and knock. It may be just me but boost hits REALLY hard with the 10:1 compression. I've driven cars with the same boost kit and running at 10psi but witht he 8.6:1 compression and talk about boost lag.

I think a lot of people have the old thinking that higher boost needs lower compression based on older engine designs (i.e. 4g63, etc). But most dont understand that our engines (specially the 420a) have been very well designed to resist detonation even in extreme situations (wasnt this the first I4 engine by mitsu to be CAD designed?). Provided that you give plenty of fuel, you shouldnt have much issues IMHO but again, no one has proven otherwise.

I *am* planning to go to a 9:1 compression or maybe 9.6:1 but wont be until i really need to. My engine is built up well enough right now for 10psi, and 10psi makes me plenty of happy. Crap, i cant even get traction on 3rd gear when i hit 10psi!!!

shoot me if i'm wrong

I figured you must have started NA and gone turbo later. One could prove that "at the same hp level and all other things being equal", the lower comp engine with higher boost would be less detonation prone than the higher comp engine with lower boost. This is what I've read in my IC engines text. But, I don't think there is a simple equation to tell you how high of a compression ratio is too high and how much boost is too much. You probably have to have some expensive computer models to figure it out. But, it is standard practice of OEM to lower compression ratio on turbo engines. This is probably to reduce the chance of detonation when the dumbass owner puts in 87 octane and boosts. They have to idiot proof everything. I would love to have a reasonably high compression to have quick spool up and great power. I just don't know what limits to stay within! You've at least proven that 10:1 and 10 psi work (with enough fuel). I'm going to try to do some research and figure out what the limits are, before a rebuild.


Corbin

'95 ESI-T
HRC+FMIC+ETC...

I agree. Evenmore, I've had my engine running up to 15:1 compression..yes that is right...15:1 compression N/A and no knock on 93/94 octane. I then brought it down to 13:1 and still ran just fine. yeah my engine sounded like a diesel engine but no detonation and ran fine.

I'm sure i havent been the first one doing this.

Hmm I've never had overheating problems, well the radiator anyway. I had really hot engine bay with stage 1 setup though. Still gets pretty warm under there, damn need a heatshielf for ex manifold.

My car always runs in the middle of the water temp. unless it's warming it. I see if move like a milimeter on hot days with the AC on but that about it. Just flushed my radiator today and replaced hoses, so maybe try flusing your radiator. Does your fan stay on all the time?