92 Pickup 1uz re gear - Highway RPM issues
01-18-2024, 08:59 PM
#24
Registered User
Thread Starter
Well I have a pretty boring conclusion for you, you were right 
Im almost sure I had it set correctly but today using an external tach and a laser tach on the crank hub was able to confirm I was about 300 rpms ish off at least, after adjusting and driving up to around 40 mph I noted the RPM's that I hit and they pretty much matched dead on to the calculator numbers. Im going to wait to say for sure until I do some freeway testing at the 70 mph range but I am almost positive this was operator error on my behalf.
After all is said and done retaining the 4.3 gears and kicking up to 33's should leave me at around 2900-3000 rpms on the freeway at 80 mph which will hopefully the fastest this truck will see for long durations of time and honestly is within my comfort range for extended periods of driving. Thanks again aztoyman for the thoughts
Im almost sure I had it set correctly but today using an external tach and a laser tach on the crank hub was able to confirm I was about 300 rpms ish off at least, after adjusting and driving up to around 40 mph I noted the RPM's that I hit and they pretty much matched dead on to the calculator numbers. Im going to wait to say for sure until I do some freeway testing at the 70 mph range but I am almost positive this was operator error on my behalf.
After all is said and done retaining the 4.3 gears and kicking up to 33's should leave me at around 2900-3000 rpms on the freeway at 80 mph which will hopefully the fastest this truck will see for long durations of time and honestly is within my comfort range for extended periods of driving. Thanks again aztoyman for the thoughts
Last edited by sam12843; 01-18-2024 at 09:05 PM.
01-18-2024, 09:58 PM
#25
Registered User
I've been bitten by photo tachs that I used to use when I was field service at a Caterpillar dealership. I chased my tail more than once and learned the hard way that shiny paint, an old reflective sticker that wasn't removed or something unexpected triggered the tach.
I actually didn't question your laser tach. Especially since it matched your idle speed. What got me wondering is that I never heard of anybody looking for the gears you needed. I kept thinking what am I missing? Then plugging numbers into different online calculators convinced me there's a bad number in the calculation somewhere. I was GUESSING either the tach or speedo. Slight tire size variation shouldn't be off THAT far. The OD ratio was correct. It just bugged me enough that I couldn't stop thinking about it so thanks for the closure ha ha.
I figured you would verify things like you said. Glad you got it, Enjoy driving that beast now. You're going to surprise a few people.
I actually didn't question your laser tach. Especially since it matched your idle speed. What got me wondering is that I never heard of anybody looking for the gears you needed. I kept thinking what am I missing? Then plugging numbers into different online calculators convinced me there's a bad number in the calculation somewhere. I was GUESSING either the tach or speedo. Slight tire size variation shouldn't be off THAT far. The OD ratio was correct. It just bugged me enough that I couldn't stop thinking about it so thanks for the closure ha ha.
I figured you would verify things like you said. Glad you got it, Enjoy driving that beast now. You're going to surprise a few people.
Thread
Thread Starter
Forum
Replies
Last Post
mikedog
95.5-2004 Tacomas & 96-2002 4Runners
8
12-15-2003 09:52 AM
