Redline, tuning, and speed.

[WHOOPhondaASS]

I have the sohc quad 4, and am considering raising the rev limiter, what is it set for now and how high is safe for a stock engine? Also, I have a damn 4 speed auto and want to know if it would damage it at all to go 140 mph? I have no governor on my car and I don't want to go any faster than 130 unless I know for sure.

[Fishman]

Sorry, I don't know, try asking the old guy.

Originally posted by WHOOPhondaASS
I have no governor on my car

You sure about that? I have a 95 with a 3.1L AUTO, and the governor is at 120 Mi/h

[4kQuad]

I believe the Computer that runs the car, is the govner that controls the RPM's.

So you will have to get a new chip for the computer that control your car.

[Matt95GT]

Mantapart and others have experimented with raising RPM revlimiter. They decided not to in their chip since they saw no performance gain b/c the powerband drops sharply after redline. In addition to dropping out of the powerband, it's not worth the risk of floating a valve and/or causing engine damage. This was all tested on DOHC Quad 4's.

A SOHC Quad is going to have most of it's peak power mid-RPM, much like a pushrod 2v / cyl. Raising the revlimit would be pointless since there's no more power to be had up there... the engine doesn't breath as well as the 16v cousin.

I highly doubt the SOHC / auto could reach 140 MPH if it wasn't speed governed. If you really want to disable the speed governor, connect a switch in-line to the VSS signal. When the switch is off, no governor, and no speedometer.

Aside from all that... good luck getting a chip. The DOHC's have few options, limited only to a couple of years. I'm not positive, but I've never seen a chip for the SOHC. The chips don't do much anyway... much of the Quad 4's PCM is very simple, so not alot to gain over the stock PCM's program... unless you are running boost or massive amounts of engine mods (ie internal parts machined, etc)

[WHOOPhondaASS]

I have a friend with a snap-on computer, and since my car is obdI, we can change the governor to whatever I want, Im setting it to 160(but I don't expect to be able to go over 140 in my car) Also, raising the redline in case of future mods. What else should I do?

[WHOOPhondaASS]

Also, Aerodynamics are higher concern to me than anything. I don't want to get to 140 and have the car get all squirley on me, so Im going to lower it first and buy air spliters. What's the fastest you have ever heard of a quad 4 going?

[WHOOPhondaASS]

Also, I have the four speed auto, not the 3spd.

[Matt95GT]

Did you read any of my post at all?

On top of that, you cannot reprogram the ECU via diagnostic port. Unless you friend also has a PROM burner and empty PROM chips, AND has the existing PCM code to modify, it ain't gonna happen.

[WHOOPhondaASS]

It's already done. He has a better computer than most dealerships have. His dad had to close his shop, so now he can mess with it all the time. He did the same thing to his '91 6cyl firebird.

http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=74301&group_ID=17428&store=snapon-store&dir=catalog

Thats exactly what he has, and all the software for Audi, BMW, Toyota, Porsche, etc. It will only change the Computer in obdI cars. OBDII can be moddified, but only once for some reason. I have no governor on my car- acually we just set it for 255mph. And found out I needed a new crank shaft position sensor, a throttle position sensor and that there was a TSS buletin.

[Matt95GT]

BS.

1. The tool in your link is a diagnostic scan tool / data logger.
2. The PCM code is BURNED into the PROM. You CAN'T change it without swapping the chip.

[BadBoy]

i have a '94 SOHC w/ a 5-speed, and unless you have 140 mph wind at your back, i can't see this happening. at those speeds, the wind resistance would be too much for the engine to handle. good luck to you tho! i would personally do a SOHC to DOHC conversion. the SOHC motors are junk; make only 120-125 HP.

just my :penny:

BadBoy :cool:

[1992grandam]

they make 115 hp and 135 lbs tq if i remember right....i used to own a 92 auto SOHC....SLOWEST car ive ever driven...you will honestly be lucky to hit 105-110 in that car...VERY lucky.

[Brad97GS]

You've apparently never driven an '86 Cavalier with the 2.0L engine. At the time, I believe it made 85 hp or so...

[1992grandam]

yeah...now that i think bout it i drove an 89 beretta with the 2.0 FI....that was slow but thats beside the point that this guy has to be smoking sumthing to think that that car can get anywhere near 140.....the new 3400s would be lucky to hit 140 if there was no gov. and they have 80 more hp and lbs tq...