Okay here's the deal, my Rpms don't seem to match what everyone is reporting for 70mph and nor does my topspeed on 31s.

At 70, it's turning 3400 rpm.  With stock tires the speedo was 1mph fast.  With 31s it's about 12% different (tires run short).

I was also under the impression that 31s would limit my top speed considerably.  A little bird told me the speedo will touch 80 with only light pressure. And still my Rpms are just below 4k. Were there any other gearing options out there that were higher for a 95 4dr with a 16 valve auto?  And if there was why is a motor with 160k miles on it pulling them with no problem?

My only worry is in my experience with small engines in offroad bikes, they tend to run best right before they fly to pieces.

I have new plugs (according to PO, changing to ngk gapped properly Sunday) new wires, new distributor, new injectors (i was told), new fuel pump (i was told), new airfilter and the magnaflow exhaust from the collector back.  None of these things should give it the performance that it has in my mind.  Especially since I have a surging idle from 3-800 rpm sometimes.  Egr needs cleaning I'm guessing.

Please, any ideas.  Don't want this thing to implode without me planning for it.

EGR may need clearing, but I would pull the heat shield off of your exhaust manifold and see if you have a crack, usually between the number 3 and 4 cylinder.  Mine had that issue and would often give me a weird idle now and then.

31's reduce your power while climbing hills, but on flat ground you shouldn't see to much of an issue.  If your worried about gearing you can take a look at a gearing calculator, I use http://www.solemnwarning.net/transmission/ myself.  Looking at your RPM's at 70 it looks like your right on target. http://www.solemnwarning.net/transmission/?id=98  In 96 they swapped to a lower gear in 5th, that is where your 400 RPM's are probably going.  With a .79 5th instead of the .86 you will see 3090 in 5th gear.

I take it you have the 5 speed or 4 speed auto?

With a stock exhaust it wouldnt be as peppy. Sounds like your results are about normal for a 4spd auto and 31's. IMHO a far better trans to use with 31's than the 5spd or 3spd.

With a stock exhaust it wouldnt be as peppy. Sounds like your results are about normal for a 4spd auto and 31's. IMHO a far better trans to use with 31's than the 5spd or 3spd.

I was going over the ratios, the 3 speed is nice because it gives you a longer throw in 1st and not as harsh of a jump between 1st and 2nd.  The downside is no cruising gear for the highway and a taller 1st.  More limited but I think it makes a good case for trail centric rigs.

4-Speed:
2.83
1.49
1.0
0.73

3-Speed:
2.40
1.47
1.0

I would LOVE to have that .073 4th gear in mine for the highway. But after about 75 mph mine gets too squirrely anyway.

Quote from: talonxracer on January 27, 2012, 09:12:40 AM

With a stock exhaust it wouldnt be as peppy. Sounds like your results are about normal for a 4spd auto and 31's. IMHO a far better trans to use with 31's than the 5spd or 3spd.

I was going over the ratios, the 3 speed is nice because it gives you a longer throw in 1st and not as harsh of a jump between 1st and 2nd.  The downside is no cruising gear for the highway and a taller 1st.  More limited but I think it makes a good case for trail centric rigs.

4-Speed:
2.83
1.49
1.0
0.73

3-Speed:
2.40
1.47
1.0

One thing to remember about auto transmissions is that the Torque convertor acts as a variable ratio gearbox on it's own, approx 1.88:1 at stall speed thru 1:1 at convertor lockup. So each gear will be far deeper than compared to a manual trans gear selection.

The only ratio that was put in 95 4 doors was 5.12.  That's not saying someone didn't swap in some 4.62s or 4.30s.
My 95 4 door with the 5 speed (.795 5th gear) runs right at 3500 at 70mph.  With 215/75 tires the speedo is pretty much right on.

Some 16Vs just seem to run better than others.  I had a 4 door with 200K on it and it seemed to run better than most any other 16V I had with under 150K on it.

The 3speed is a great little transmission, stout. I had played around with a few of it's bigger stablemates on the GM ranch, LOL the th 350 and 700r4. The auto trans are not all that hard to work on, no more difficult than an engine really, just a few specialized tools. I know alot of mechanics that think some sort of advanced physics or vodoo magic occurs between the input and output of a auto trans, LOL