head gasket

[boost_boy]

ok great.. thanks alot guys.. looks like as soon as i get the head checked out.. ill be spraying the gasket.. are you guys saying to spray the head bolts as well or not?

No need to spray the headbolts.

Dee

[boost_boy]

i believe on the copper spray thing for re-used metal gaskets, on my first assembly, my HKS 1.6 (3 piece metal) had a coating, but when i re-used it you can see it was gone in places, we cleaned teh surfaces and sprayed it with copperspray.. its sealing perfect, seen 20psi, T3/T4E stock slugs and rods

slightly off topic: why do all the high comp, cams, intake, exhaust end use a tiny turbo?? get a bigger GT25/28 (GT2871R ) sized turbo or T3/T4 hybrid and get the better response from the high comp and better numbers/power..

Most people want immediate response from their engines and feel that they can possibly get a better kick out of the CA18DET by raising cylinder pressure via a change of pistons. Ryan or float_6969 knows 1st hand that this is a tricky ordeal. Timing in this case is key and will make or break this high compression and turbo combination. No matter what we do, the CA18DET is a turd under 3000rpm, so I took advantage of that 1000-3000rpm laziness and added a turbo that doesn't start kicking butt till around 3500rpm till redline. But for autoXers, they see the turbo/high compression thing as assistant in achieving their goals.

Dee

[float_6969]

Dee is pretty much dead on here. I think if I can get my hands on a RWD CA18DET rear end, (lower gearing) it should keep the CA on target for autoX. I've got my first race w/the CA on Sunday, so we'll see how it goes. I'm still running the KA gearing right now though (4.083:1), so I'm not expecting a whole lot.

[biosehnsucht]

I think I've sourced a 4.375 (almost stock gearing, should be 4.363, but instead of being 7% too slow it'll be something less than a percent too fast, not going to be a meaningful difference) from jdm-land, it'll be awhile before I get my hands on it..

[CA19DET]

well i was thinking flat esp, has full controll with timing etc.. but i see for auto-x, but still cant see you going below 4000rpm anyway, but hey..

and more off topic, i am running a 3.7 or something rear end from who knows what JDM nissan, i really need to step up to the 4.3~ anyone have just a ring gear to sell???

[tyrannix]

ive been looking for CA diff gears for a while now, since i forgot to grab mine when i stripped the car :\do you have a source, that could get another one?

[CA19DET]

i have a stock CA18 R180 open diff i was about to weld up, you need a R180 ring gear if so, i have one

[nismo_chk]

ok.. umm.. i guess this thread is pretty much done with for now.. u guys are horrible at staying on topic.. lol

[knightrider]

im going to prolly go with 9.5:1, my boss is the one that wants to go 10:1, hes crazy like that, also im using a disco potato because JWT was the main influence for the turbo, and my boss will give me one for free, so i dont complain. all i do is buy some of the parts, the rest are given to me.

[Coldspawn]

Knightrider, from experience, don't go with the 10:1 unless this is going to run race gas only.

I am curious why you say that.

[themadscientist]

detonation due to low octane pump gas. These J-spec turbo engines are designed to rum on Japan-market 100 octane not wawa regular.

[float_6969]

I am curious why you say that.

with 9.5:1 on my CA, I can't run safely run more than about 20* of total timing @ 7psi on 91 octane fuel. It doesn't detonate all the time, but will occasionally. Granted this is a rough tune, and I still need to get to the dyno, but I would think 10:1 would be considerablally worse.

I'm not saying that you CAN'T run 10:1 w/boost on pump gas, you'll just have to pull a lot of timing out of it. The 10:1 would make for a nice low end on the CA though. I know that it's a night and day difference with the 9.5:1, but the CA is still kinda gutless down low, it's just tolerable now...

PS-I've currently got it tuned to run about 15* of timing @ about 7psi, but this is a VERY conservative number, and I think with a better fuel curve, I could run 17/18* on pump gas.

[Coldspawn]

with 9.5:1 on my CA, I can't run safely run more than about 20* of total timing @ 7psi on 91 octane fuel. It doesn't detonate all the time, but will occasionally. Granted this is a rough tune, and I still need to get to the dyno, but I would think 10:1 would be considerablally worse.

With bolding that, how do you know you are not adding too much timing? When I say that, I mean. There is a point where you not making power and it is before the knock threshold.

I'm not saying that you CAN'T run 10:1 w/boost on pump gas, you'll just have to pull a lot of timing out of it. The 10:1 would make for a nice low end on the CA though. I know that it's a night and day difference with the 9.5:1, but the CA is still kinda gutless down low, it's just tolerable now...

The thing about timing is this. Most people do not understand what timing actually is. They say "more boost, less timing" or "more compression, less timing". That is true, but they do not understand why that is so.

With higher compression, the cylinder will burn hotter then a lower ratio. When you add more timiing to the lower ratio, it heats the cylinder up to almost the same as the higher compression.

With saying that, if you make same or more power with less timing, the motor is actually more efficent then a motor with more timing.

[Coldspawn]

opps, forgot this

PS-I've currently got it tuned to run about 15* of timing @ about 7psi, but this is a VERY conservative number, and I think with a better fuel curve, I could run 17/18* on pump gas.

Better fuel curve? Fuel should be only used as a "coolant". The richer the mixture, the colder the cylinder temp. That is saying the ignition timing is tuned correctly.

Another thing, people think they will make more power with a leaner mixture. That is not true.

[float_6969]

Coldspawn, I'm aware of everything you stated, hence me stating that the tuning wasn't on target yet. My butt dyno tells me that I'm close, but I've still got a couple of hours of dyno time before it's perfect.

I'm currently tuned to run at or below 12:1 AFR (wideband is saying anywhere between 12.1-11.3), and the timing never exceeds 15* at full (7psi right now) boost. I'm fully aware that this is a very safe tune, and that I'm not at the motor's peak effeciency, but w/o a dyno, it's hard to safely push it much farther. I'm sure I could pull some fuel out of it and still be OK. As for the timing, I was running 20* when in boost and it knocked on me a couple of times, so I just pulled 5* out until I could get to the dyno.

[Coldspawn]

Cool cool. I did not want to see a blown motor over somwthing dumb. Good luck at the dyno.

[float_6969]

I'm ready for it. I can't wait to get full power out of this thing. I'll do my best to get some video, and definatly pics and dyno sheets.

[boost_boy]

I'm ready for it. I can't wait to get full power out of this thing. I'll do my best to get some video, and definatly pics and dyno sheets.

Be sure and call me personally when you're done and don't pop the motor

Dee

[float_6969]

LOL! Will do Dee. I'm pretty confidant that I'm not going to pop it though.