3.42 Installation Update/Questions
Thread Starter
Racer
Joined: Mar 2003
Posts: 309
Likes: 0
From: Baton Rouge
3.42 Installation Update/Questions
Guys, from my earlier post, you know I'm having problems with the speedometer after my 3.42 install. A short time ago, I did a new tune on the Predator (I was relieved that I didn't blow the car up!) I changed the factory and actual wheel size to my rear wheel size as follows:
Tire size = 275
Aspect = 40
Rim Size = 18
The speedo still seems to low to me. Here's some number to go by. When the speedometer says 60mph, my RPM's are about 3,400 and my oil PSI is about 60. Can you engineers tell me what kind of speed I would have to be going to have these numbers? The car definitely feels different from when it had the 2.73. I'm not used to the higher RPMs at all times. It feels like a horse with a whip to it!
I need some advice.
Thanks
Tire size = 275
Aspect = 40
Rim Size = 18
The speedo still seems to low to me. Here's some number to go by. When the speedometer says 60mph, my RPM's are about 3,400 and my oil PSI is about 60. Can you engineers tell me what kind of speed I would have to be going to have these numbers? The car definitely feels different from when it had the 2.73. I'm not used to the higher RPMs at all times. It feels like a horse with a whip to it!
I need some advice.
Thanks
Melting Slicks
Joined: Apr 2002
Posts: 2,397
Likes: 55
From: Dove Mountain, AZ
Re: 3.42 Installation Update/Questions (99C5Richie)
Ok, here is what I know about this. The gear scaling for 3.42's is wrong in the Predator. They know about it and it will be fixed in ver 1.4, until then you will have to get RWTD to send you the file that fixes this. I do not know who you bought it from but if not RWTD then ask them for the update. You can also as a patch change the tires size. This will of course make your speedo off, but should work until the new update. Hope this helps. :thumbs:
[Modified by TXSTICK, 5:56 PM 6/19/2003]
[Modified by TXSTICK, 5:56 PM 6/19/2003]
Thread Starter
Racer
Joined: Mar 2003
Posts: 309
Likes: 0
From: Baton Rouge
Re: 3.42 Installation Update/Questions (TXSTICK)
TXSTICK, this is exactly what happened when we installed the 3.42 @ the dealership. The Predator people emailed us a file to fix the problem. However, now the speedometer problem. Oh, well--I'll figure it out. This car is a hell of a lot more aggressive now!
Thread Starter
Racer
Joined: Mar 2003
Posts: 309
Likes: 0
From: Baton Rouge
Re: 3.42 Installation Update/Questions (Mike Mercury)
Mike, I used the information on my tire (27540zr18) as the parameters. Do you think I should have used 26.7"? If the computer thinks I have smaller tires, this could explain my low speedometer reading. If I'm asking stupid questions, forgive me, I'm an accountant!
Melting Slicks
Joined: Apr 2002
Posts: 2,397
Likes: 55
From: Dove Mountain, AZ
Re: 3.42 Installation Update/Questions (Estlupum)
I think I am wrong about the speedo since it comes off of the rear axle. The programing should not effect the speed reading, only the shift points. Sorry about the mis-information. Changing to a different tire size will , but only changing the programing for different tires will only effect the shift points. :thumbs: You might have a bad sensor in the rear. :confused:
[Modified by TXSTICK, 9:08 PM 6/19/2003]
[Modified by TXSTICK, 9:08 PM 6/19/2003]
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Team Owner
Joined: Apr 2001
Posts: 54,204
Likes: 180
From: S.W. Ohio. . . . . . NRA Life Member
Re: 3.42 Installation Update/Questions (TXSTICK)
Mike, I used the information on my tire (27540zr18) as the parameters. Do you think I should have used 26.7"?
Unless I misunderstood the Predator setup, when you enter in "275" that equates to 27.5 inches... and not "275" that denotes the "series" of tires.
Since I have never had to do this specific changewith my Predator... I am guessing here.
Do you remember the figure that was originally entered for your rear tires?
Thread Starter
Racer
Joined: Mar 2003
Posts: 309
Likes: 0
From: Baton Rouge
Re: 3.42 Installation Update/Questions (Mike Mercury)
Mike, I don't remember what the original was because the guys at the dealership did it for me. Like the person's post above said, when the initial predator program was installed, they were having trouble with the shift points. They called Predator and they said to adjust the tire size and then sent us a file to upload. The shift problem seems OK now, but the speedometer is off. The dealership guys have been helpful, but it looks like I'm going to have to take another trip to New Orelans to get them to work on it. What did you think about my RPM levels in my initial post?
Team Owner
Joined: Apr 2001
Posts: 54,204
Likes: 180
From: S.W. Ohio. . . . . . NRA Life Member
Re: 3.42 Installation Update/Questions (Estlupum)
if you want to check the calibration of your speedo, just drive a constant 75 mph in 3rd gear (making sure the TC is locked). Your RPM should be 3420.
if it's not, then try to drive (in 3rd gear) at a constant 3420 rpm and look at your speedo. This will tell you how far your speedo is off.
[Modified by Mike Mercury, 1:00 PM 6/20/2003]
if it's not, then try to drive (in 3rd gear) at a constant 3420 rpm and look at your speedo. This will tell you how far your speedo is off.
[Modified by Mike Mercury, 1:00 PM 6/20/2003]
Burning Brakes
Joined: May 2002
Posts: 970
Likes: 3
From: brooklyn ny
Re: 3.42 Installation Update/Questions (Estlupum)
Forget reprogramming with the predator. It probably won't work. I used a Hypertech and its crap. Used a Superchips unit and it worked like a charm. p.s. 34oo rpm at 60 is really too low . Did't you notice you were passing everyone? You were doing about 80+
Drifting
Joined: Jun 2001
Posts: 1,934
Likes: 5
From: Mount Vernon Arkansas
St. Jude Donor '12-'13
Re: 3.42 Installation Update/Questions (ken-rx)
"Forget reprogramming with the predator. It probably won't work."
:bs
The Predator works just fine. Re-enter the proper tire size. The problem is with the rearend scaling and the trans not shifting and hitting the rev limiter. That can be corrected with the file they sent you. I went thru the same thing and James, at Runninwiththedevil.com, sent me the correct file. Contact him as he will probably be more than happy to help, especially if you bought it from him. Great customer service!
:bs
The Predator works just fine. Re-enter the proper tire size. The problem is with the rearend scaling and the trans not shifting and hitting the rev limiter. That can be corrected with the file they sent you. I went thru the same thing and James, at Runninwiththedevil.com, sent me the correct file. Contact him as he will probably be more than happy to help, especially if you bought it from him. Great customer service!
Race Director
Joined: Oct 2002
Posts: 16,477
Likes: 26
From: Gone
CI 6-7-8-9-10 Veteran
St. Jude Donor '03
Re: 3.42 Installation Update/Questions (Mike Mercury)
Ok, I don't really know anything about how the C5 speedo works or the Predator...but if he did enter 275, which was programmed in as 27.5" and he really has a 26.5" tire...the speedo would be reading faster than his actual speed, the opposite of his problem, and not nearly to the degree of error he is experiencing.
Shorter tire = speedo reads faster than you are actually going.
Taller tire= speedo reads slower than you are actually going.
:cheers:
Shorter tire = speedo reads faster than you are actually going.
Taller tire= speedo reads slower than you are actually going.
:cheers:
Melting Slicks
Joined: Apr 2002
Posts: 2,397
Likes: 55
From: Dove Mountain, AZ
Re: 3.42 Installation Update/Questions (Y2Kvert4me)
Question is, can the speedo be changed with programming? I thought since it comes off of the axle that only tire dia will effect it. :confused:
