4.10 axle questions RPO G44 G92 ['89 L98 auto]
10-15-2006, 06:14 PM
#1
Racer
Thread Starter
4.10 axle questions RPO G44 G92 ['89 L98 auto]
I have a 1989 C4 with the L98/auto. At this point I want to leave the motor stock and only modify the rear differential. I need to learn all considerations before spending money. Over the last 2 years I spent way more to modify my 2000 Civic Si than I paid to get a C4 in August. I can't have a Corvette that is slower than my 1.6L Civic. I figure the rear diff should take care of that.
I am confused. I'm trying to use proper netiquette and search before asking questions. I found G44 and G92 codes on my RPO sticker.
taken from the C4 RPO thread:
So - Does this mean I have a D36 with a 3.07?
Also - when changing the rear differential ring and pinion, how will that effect the following:
ECM
emissions testing
top speed
highway gas mileage
highway crusing RPM
I would imagine that RPM's vs. speedometer will increase across the board and gas mileage will decrease. I would also imagine that the top speed will drop, not that I need to be driving that fast anyway.
Will the ECM need to be modified or recalibrated? How will this effect my California emissions testing?
What is a good brand to buy and what is a reasonable price to pay for parts and labor? (I'm a do-it-yourselfer, but I'll leave the ring and pinion to the experts)
What else should I consider?
I am confused. I'm trying to use proper netiquette and search before asking questions. I found G44 and G92 codes on my RPO sticker.
taken from the C4 RPO thread:
Rear Differentials
This topic gets picked on quite frequently. Time to clarify it. There are two differentials, the D44 and the D36 (not RPO codes), both made by Dana. The D36 is standard on the automatic and the D44 is standard on the manual, expection being 1984, when the D36 was the only one available.
These are the codes related to the rear gearing, with the differential that they use:
G44 - 3.07 Rear Axle Ratio - D36, optional; D44, standard, pre-1992.
G92 - Performance Axle Ratio - Shows performance axle selected.
GHO - 3.54 axle ratio - D44 only.
GM1 - 2.59 Rear Axle Ratio - D36 only.
GM3 - 3.45 Rear Axle Ratio - D44 only.
GU2 - 2.73 Rear Axle Ratio - D36 only.
What this means is this, G92 is not dependant on a specific ratio or differential housing. It's just an indicator, a rather redundant one when you think about it.
This topic gets picked on quite frequently. Time to clarify it. There are two differentials, the D44 and the D36 (not RPO codes), both made by Dana. The D36 is standard on the automatic and the D44 is standard on the manual, expection being 1984, when the D36 was the only one available.
These are the codes related to the rear gearing, with the differential that they use:
G44 - 3.07 Rear Axle Ratio - D36, optional; D44, standard, pre-1992.
G92 - Performance Axle Ratio - Shows performance axle selected.
GHO - 3.54 axle ratio - D44 only.
GM1 - 2.59 Rear Axle Ratio - D36 only.
GM3 - 3.45 Rear Axle Ratio - D44 only.
GU2 - 2.73 Rear Axle Ratio - D36 only.
What this means is this, G92 is not dependant on a specific ratio or differential housing. It's just an indicator, a rather redundant one when you think about it.
Also - when changing the rear differential ring and pinion, how will that effect the following:
ECM
emissions testing
top speed
highway gas mileage
highway crusing RPM
I would imagine that RPM's vs. speedometer will increase across the board and gas mileage will decrease. I would also imagine that the top speed will drop, not that I need to be driving that fast anyway.
Will the ECM need to be modified or recalibrated? How will this effect my California emissions testing?
What is a good brand to buy and what is a reasonable price to pay for parts and labor? (I'm a do-it-yourselfer, but I'll leave the ring and pinion to the experts)
What else should I consider?
10-15-2006, 06:17 PM
#2
Le Mans Master
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Originally Posted by juanathandavid
I can't have a Corvette that is slower than my 1.6L Civic.
Dont worry you dont
10-15-2006, 06:20 PM
#3
Race Director
You'll have to upgrade to a D44 to run 4.10 gears. Also, 4.10's are waaaay too much gear for a stock L98. Stick with the 3.07's, if that's the gears you are running.
10-15-2006, 06:22 PM
#4
Burning Brakes
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IMHO you have the right ratio for a basically stock L98 auto. Even if you added long tube headers with a good catback and a little looser converter(also IMHO the best bolt on for the buck) you would still not really need more than what you have.
10-15-2006, 06:26 PM
#5
Racer
Thread Starter
Originally Posted by Invanity
Dont worry you dont
Originally Posted by STL94LT1
You'll have to upgrade to a D44 to run 4.10 gears. Also, 4.10's are waaaay too much gear for a stock L98. Stick with the 3.07's, if that's the gears you are running.
10-15-2006, 07:29 PM
#6
Drifting
the l98 is a low rpm torque monster.it is out of breath by 4500-4800 rpm IIRC.that would be a waste of the power band on your motor.you would run out of rpm's in a hurry.you don't need alot of gear with the wide torque band you have.3.07 is ideal.even modified l98's rarely run more than 3.45 gears.
10-15-2006, 09:25 PM
#8
Originally Posted by juanathandavid
Trust me...I took my time when I built that motor. almost 12:1 c/r on pump gas, self-tuned on a hacked obd1 system.
If your L98 is slower than your Civic then you need to connect the other two spark plug wires.
Originally Posted by juanathandavid
Good to know about the axle. However, please educate me on why the 4:10's are "too much gear". Seriously, I'm ignorant. I figured this would be the way to go. What about perhaps a 3:54 or 3:73?
10-15-2006, 10:59 PM
#9
Racer
Thread Starter
Originally Posted by Vis Croceus
If your L98 is slower than your Civic then you need to connect the other two spark plug wires.
How did you build a vette-killing Honda without understanding how to pick a gear ratio?
I was thinking about just that a little while ago. The honda's final drive is 4.4, but duh, it is a 5speed manual and revs past 8000rpm.
Forgive me, I'm very new to the wonderful world of the C4.
10-15-2006, 11:14 PM
#10
Race Director
I ran 3.73 gears in my former 86..it was very fast off the line but I never 1/4 miled it and from a standpoint from the forum,it may have hurt 1/4 times if I was to compare it to a 3.07 rear.Racers on here have proven time and time again the 3.07's are ideal for the total package.
If 0-60 stoplight stomps are all you care about,then a steeper gear,no more than 3.54 or 3.73s are all you want to do.
Let me add one of the reasons I went with the steeper gear ratio,I had planned to add a Miniram to the engine and a 2800 stall converter for the automatic trans....I never got the chance to do it...That was set up goal was ideal,but if youre running the stock/or large tubed TPI,and are not going to change the intake,it may not be the best move.
If 0-60 stoplight stomps are all you care about,then a steeper gear,no more than 3.54 or 3.73s are all you want to do.
Let me add one of the reasons I went with the steeper gear ratio,I had planned to add a Miniram to the engine and a 2800 stall converter for the automatic trans....I never got the chance to do it...That was set up goal was ideal,but if youre running the stock/or large tubed TPI,and are not going to change the intake,it may not be the best move.
10-16-2006, 12:42 AM
#12
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Your expectations are correct for everything, and this doesnt effect emissions. It will need a calibration for the speedo, but otherwise nothing. You do have D36 3.07, which is perfect for the L98 automatic. I would not change it to anything lower unless you find a deal on a D44.
However, there is no way I'd run a 4.10 D44 rear in an automatic that will be driven on the street, ever. Doing such a mod first dictates everything to follow that must be done to the intake, and those intakes arent legal in Cali.
However, there is no way I'd run a 4.10 D44 rear in an automatic that will be driven on the street, ever. Doing such a mod first dictates everything to follow that must be done to the intake, and those intakes arent legal in Cali.
10-16-2006, 04:08 PM
#13
Le Mans Master
I had 4.09 and an automatic in mine. I liked them but I changed to a 3.73 because im getting ready to add a supercharger. But keep in mind I have a LT1 with ported heads, hotcam, headers etc.
If I still had a L98 I would start with a higher stall converter, headers and a better exhaust. Then intake, heads, and cam. Somewhere in there you will be needing a D44 diff. to replace the weaker D36 that the autos came with. But before modding, drive it awhile and do some research.
Oh, and for those that dont think there are hondas out there faster then vettes, need to get out to the drag strips more often.
At my local 1/8 mile track there is a guy who works for Hendricks Honda and he drives a Black Civic. He DROVE it to the track and I ran him. I ran a 7.76 at 92mph and he ran a 7.80 at 102.7 mph. He was on street tires and did not get a good launch. With slicks he runs mid 10sec. times at MIR which is a 1/4 mile track. Go out to one of the import vs domestic races and you can see some fast hondas.
But dont believe that just because you drive a vette that there are no hondas that can beat you.
If I still had a L98 I would start with a higher stall converter, headers and a better exhaust. Then intake, heads, and cam. Somewhere in there you will be needing a D44 diff. to replace the weaker D36 that the autos came with. But before modding, drive it awhile and do some research.
Oh, and for those that dont think there are hondas out there faster then vettes, need to get out to the drag strips more often.
At my local 1/8 mile track there is a guy who works for Hendricks Honda and he drives a Black Civic. He DROVE it to the track and I ran him. I ran a 7.76 at 92mph and he ran a 7.80 at 102.7 mph. He was on street tires and did not get a good launch. With slicks he runs mid 10sec. times at MIR which is a 1/4 mile track. Go out to one of the import vs domestic races and you can see some fast hondas.
But dont believe that just because you drive a vette that there are no hondas that can beat you.
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