Supra Forums banner
1 - 20 of 21 Posts

· Registered
Joined
·
178 Posts
Discussion Starter · #1 ·
cammed 1jz.
fmic.
3" exhaust.
62mm IHI turbo.
full stand alone, tuned.
meth injection.
intake.
injectors.
fuel pump.

all the good stuff.
is a new 8000 rpm rev limiter ok to do without hurting the motor?
 

· Registered
Joined
·
178 Posts
Discussion Starter · #5 ·
First off this isnt me who is doing this. Not going to say who.

Why wouldnt you want to rev to 8k?
If your fuel and air can continue to make power to that rpm then why not.
 

· 25psi Bliss
Joined
·
1,534 Posts
If the head is prepped for such service, and you have the engine management to allow 8k rpm, then go for it. If not, then potential issue would be valve shim dislodging, and issues with the springs. Firstly, put the car on a dyno, and see if you're making any power (hp / tq) at the higher RPMs. Otherwise, it would be meaningless to go that high.
 

· Night in the Ruts
Joined
·
979 Posts
Check the dyno sheets from the other 1j guys that have them posted. That should give you an idea of where the power starts to fall off on the top end, then work around that number. The 7M starts to loose power at 6500 rpm, so going to 7000 with the motor is slowing it down.
 

· Registered
Joined
·
2,390 Posts
well yeah, you cant just spin the motor to 8k then shift, My power doesn't fall at 7k on 19lbs like it does at 14lbs. depending on cams and the size of the OP's back housing he might gain some ET shifting higher, or he might not. I dont really use the dyno to determine this because the dyno only shows how 4th gear looks and I don't cross the traps at the top of 4th..

HEY OP what ECU are you running?
 

· *************************
Joined
·
2,922 Posts
There is no reason to rev that high...there is no reason to even rev near redline period...if I were you don't but that's just me
We're not talking about a 7m here. Redlines don't mean shit unless you're stock in which case you won't make power past the redline anyway...
 

· Registered
Joined
·
178 Posts
Discussion Starter · #15 ·
If I shift at 7k I lose 3 tenths. shifting at close to 8k gives me the best results. and my powerabnd is different on more boost. that dyno is just on 14 lbs
In this case it makes complete sense to shift at higher rpm.

Think even if you are not making power past lets say 7000 that extra 1000 rpm will allow your next gear to start 1000 rpm higher if you shift at 8000 instead of 7000.

Thus giving you better acceleration.
 

· 25psi Bliss
Joined
·
1,534 Posts
In this case it makes complete sense to shift at higher rpm.

Think even if you are not making power past lets say 7000 that extra 1000 rpm will allow your next gear to start 1000 rpm higher if you shift at 8000 instead of 7000.

Thus giving you better acceleration.
The previous responses rejects this idea.

For best acceleration, you want to keep the car at all times in it's optimum power band through all gears, otherwise, you're just wasting time.
 

· ma70-7m=1JZ
Joined
·
2,602 Posts
When I had my MInes ECU the rev limit was at 8000 rpms, it was great I ran this way for years, I am running custom usdm 2jz cams in my 1j. Now with the Haltech PS2000 I have the rev limit set at 7750. I never had any problems reving to 8K, but obviously its hard on the motor, although remember the under square stroke of the 1jz, the stroke is 7x mm vs the 86 mm bore, so in comparison to the 2jz the piston speeds are way down. With upgraded valve springs and cams, I dont see why not.

I do find though in the 1/4 if I keep it in 3rd gear at the top end of the track, I get a slightly lower ET, but if I shift to 4th just before the end of the track my trap speed is up 1-2 MPH. This is because of the extra tourque available in the mid rpm range after the up shift.
 

· Registered
Joined
·
178 Posts
Discussion Starter · #18 ·
The previous responses rejects this idea.

For best acceleration, you want to keep the car at all times in it's optimum power band through all gears, otherwise, you're just wasting time.
Its impossible to keep it at your optimum power band through every gear. If you shift earlier you will have to go through more rpm to reach your optimum power band in the next gear.
 

· Registered
Joined
·
178 Posts
Discussion Starter · #20 ·
ok that it what i was told befor and just wanted to hear someone else say it.

thanks guys.
 
1 - 20 of 21 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top