rdm20fan

Hey Guys,

I've been pushing my 1st gen 1UZ more this past year.
I had a couple problems and I wanted to share.
Maybe a few of you have had the same issues. Here is what I have learned.

13-14 PSI about 450 RWHP issue
I blew out a stock head gasket (Composite) a few years ago right at about 14 psi.

With my rebuild I used the GS400 head gasket (MLS) at 14 psi I would start blowing coolant out of the radiator overflow. This was probably about 450HP to the rear tires. At this point the Toyota head bolts are stretching allowing the compression to get past the gasket, and into the coolant passages. This builds pressure in the cooling system, and pushed the coolant out. On a composite gasket this pushes the gasket out of the way, and you have a head gasket failure. With the MLS gasket it allows the pressure past, but usually re-seats itself when the high cylinder pressure stop.
I kept wasting time chasing over heating issues, when I should have been putting in new head studs.

20 PSI About 600 RWHP issue
Same thing as before, but I was running ARP head studs. It's hard to sometimes think of a bolt acting like a spring, but under the high cylinder pressure the combustion is enough for the bolts/studs to actually stretch until the pressure is gone then they pull back. This is usually the case until it is to much for the bolt/stud to take and it stretches past the point where it will not spring back.

The reason I listed my boost PSI, and what I think the car was making HP level is because I'm pretty sure it doesn't matter how you are making the HP. (Turbo/Supercharger/Nitrous/High Compression, cams) The combustion pressure to make that level of HP is what is lifting the head, not that actual 21 lbs of boost.

23-24 PSI close to 700 RWHP issue
Since the head gasket was re-seating itself after each pass down the drag strip. Chris and I decides to try and up the boost level, and just blow coolant into the over flow.
After each pass we would just drain it, and refill the cooling system in order to try and run a 10 sec pass
(We didn't get there this year)
The motor started breaking up in 4th, 5th gear when the boost levels would get that high.
We were blowing out the spark. The velocity of that amount of air rushing into the cylinder was to much for the coil to continue to drive spark across the sparkplug gap.
We re-gapped the plugs to a smaller gap, and it got better, but didn't go away. At 25 PSI the motor was breaking up and wouldn't make any power.

Don't know whats next for my 1UZ. I was thinking of O-ringing the Heads/Block.
Also thought of having the Block/Heads drilled, and tapped for larger studs.
Next would be to also get new MSD coils.

To o-ring, and drill new head studs will probably lead to long periods of down time for the car, and I don't know if that's the route I want to go right now.
The SC is pretty fast as it is. Maybe turning the boost back to 15-17 psi, and enjoying her for a little bit might be a good place to be for a little while.

What do you guys think?
Hope this helps someone going through the same.

Thank, Bob

1997Soarer

iTrader: (1)

I'd turn down the boost for now and enjoy it like you say. But then again, that's me. I've been NA for years and i keep finding little things that make driving the car more enjoyable (one of the main reasons I didn't try to do a turbo kit).

You can always just turn the boost up again and keep pursuing lower drag times. Especially if you find that the more enjoyable of the 2 options

rdm20fan

Hey Brian, it's Bob. I think you're right. I think Chris and I are going to try and paint the car this winter, and maybe cruise it a little more.
How are things with you?
Bob

czar07

Im surprised you havent run 10s with 700hp. We have Soarers in Aus running 10s @ 130ishmph on 500rwhp (Single turbo 1JZ).

rollexus

Sometimes less is better. This is one of those cases where a single turbo trumps twins....

rollexus

Very Interesting..... My guess? The energy will still need to go somewhere. After tightening up everything with bigger head bolts, be ready to see a perfect split right down the middle of the engine block. This will probably happen somewhere in the middle of the runway while slapping it from second to third at 8200rpm.

These darned engines are just not having it.... +1 for turn down the boost and enjoy the car for what it is. Seems like 500-600 is the most we can get from these guys safely and on pump i'm taking it?

Kind Regards, and congrats for completing this project Bob.

Nick from Toronto.

rollexus

Factory gapping for this car is 0.041 going down to 0.035 and adding an MSD ignition will defiantly help with the misses. Maybe even burn more of that forced air before the pressure lifts the heads? Hmmmm....

rdm20fan

Not on a full weight car they aren't. Trap speed is a basic problem of hp versus weight. Not to mention 500hp on a 1jz is probably close to 40psi.
As far as et, they may be launching harder then I am, and leaving under boost. This is a street car. With the mph the car is running, and better practice it should run in the 10's
So far to date an 11.20 and 133mph is its best.


Thanks Nick,
I don't know if the projects are ever "complete" but I have gotten to a good milestone. My goal for this year was 120mph trap speed. The cars first run was 119.9
The car is at the shop, and we have started taking the body apart to make her look pretty again.
I think a TT v8 with a 6-speed running about 15-16 psi that looks pretty is going to be the goal for next year.
Maybe o-ring the head, and larger studs down the road.

Vrank

iTrader: (4)

The real problem with this project is the lack of understanding in math/physics along with a hearty helping of pulling things out of asses. I seriously think understanding might help you get there, but the fact you believe it must take 40psi to make 500 on a 2.5L shows you're a ways off from reaching that point.

There's so many variables that equate to hp. Ten psi from a pair of ct12s vs 10psi from my s363 is 100% different.

Maybe learn about suspension, make some changes, and look for those 10s.

rollexus

In regards for the displacement of fuel, to air, to fire that you are throwing in your engine, I would crank out some numbers and follow through with the MSD ignition system, and correct gapping on the spark plugs. From there, dyno tune, dyno tune, dyno tune.... This before I would open up that engine again. Not again!

Hey Bob, I almost forgot, this is one of the few FI projects that is running a 6 speed. The only one that I know of that is running a TT getrag. I have a few questions if you don't mind. Did the factory V161 cross member fit for your swap? Or did you need a modified one as did ScottURNot. I'm leaning more towards "alignment", and having that X-member line up just seals the deal yeah? Second question is, we have all the major parts (ie, tranny, rear end, trans tunnel, slave cylinder, pedal) even the adapter from TTC (which we will check for center before running it). The question is, can we talk about your six speed swap? I may even ask you to kindly ask Chris for an adapter plate that you guys are using, as I lack confidence in the one I have. Pretty please .

PS Milestones are a testament to success

Nick from Toronto.

Ali SC3

iTrader: (10)

just up the spark with MSD boxes at the least. what ecu are you on? if stock its tougher but you could run individual coils if on aftermarket. with stock you can do it with an IGF simulator and run some GM coils even.

czar07

You are correct its running a stripped out interior. I believe he is on 25psi on a 6262 precision.
I think the auto helps him a lot more though

99SC42

iTrader: (44)

^^ Thank You

rdm20fan

I apologize if I offended you. I don't know what it takes to make power on a 1jz.
I honestly didn't find it as a reasonable option for me, as it would add a lot of weight and lose hp and torque all in the name of aftermarket support.
I felt the aluminum v8 was more desire. I simply ment the comment as it would require a lot to achieve 500hp on the small displacement.


Hey Ali, what is a IGF simulator.
The 1uz runs 2 coils, and 2 distributors (first gen)
I think I'm going to try and change out the stock coils for a couple of msd, or Malory coils.
See what that does.


Hey Nick,
I'm running a v160 basically the same as the 161.
Chris made his own ring. It's a 1 piece ring that bolts to the motor, and has threaded studs that the trans slides on, and nuts hold it.
He did this at least a year before cowboy bebop made his ring. Chris and I also went to quarter master and had them design the clutch for the 1uz-getrag dual disc.
Chris was going to try and make a ring, but cowboy kind of took the idea and ran with it.

There are a bunch of photos, and a write up on lextreme.com. Just do a search for rdm20fan.
I am using the stock trans crossmember. If I remember correctly we turned it around. We did make the trans mount using a couple BMW engine mounts we had at the shop. Drilled 2 new holes, and I think that was about it.

Tuning has been something I've been doing for each run. As far as wide open throttle, I think the car is good. I don't go leaner then low 11's most of the time the car is in the 10's for AFR.
I look at my air fuel after each run at the track.

99SC42

iTrader: (44)

First question what fuel are you using?