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People have gotten 3.42 from manual C5 to put behind automatic and higher stall torque converter and made car quicker.
Edit. The gear ratios for the 4L60E are:
1: 3.059.
2: 1.625.
3: 1.00.
4: 0.696.
R: 2.294.
Thanks 3.15s i couldn't find the trans gear ratios similar to finding the 6 speed ratios. So OD of an a4 is pretty much 5th of a 6 speed and 3.42s would make it similar to driving a 6 speed in 5th. 4.10s would be way too high of a gear for a mostly street driven vehicle. It does 80mph easy on the highway with the headers, cam if you dont use cruise control at 70mph so 3.42s someone told me puts it at 70mph 2200rpms. Most people do 70-80mph on the highway im trying to calculate speed given certain ratios the car drives best at 2200 rpms.
I really dont want to do a torque converter just yet but i see it in the future as the car is a dog when normal driving and gear selection isnt there as it is with a 6 speed around low mph turns and such gas pedaling. The cam i got is similar to stock off idle if you ask me i just notice that to go anywhere you have to floor it every time to downshift and the A4 is simply missing 2nd gear carrying a long 3rd gear before drive or 3 1-1.
The jegs xhd torque converters are roughly 500$ 2400-3600stahl and rated to 600hp dual 10.75-11.5" bolt patterns that would probably be my only option. They do say c5 fitment
Since you have 3.15 gears swapping to a 3.42 complete differential out of wrecked C5 with manual transmission wouldn’t gain as much as if you had 2.73 gears.
However with 3.42 diff I’m sure you could cruise 70-80 mph just fine, guess it depends on what you want out of the car.
Could just do the 3.42 diff and leave torque converter alone, I’ve never driven a vehicle with higher than stock rpm torque converter so no personal experience.
My 1965 C10 has 396 big block TH400 stock torque converter and 3.73 diff, it could really use overdrive bad, try to avoid freeways or stay in slow lane going 65 mph.
My C5 A4 had a 3.15 rear drive ratio but a bearing began shedding metal at Buttonwillow Raceway in 2016. Also found both Bellville springs broken in the differential. Switched to 3.73 rear drive ratio with a geared WaveTrac differential. The car is much faster on a road course with the 3.73 rear drive ratio and a differential that does not appreciably slip under high torque.
With the transmission in 4th, 75 mph is at about 2450 engine rpm, fine for cross country driving.
Going from 3.15 to 3.73 resulted in an overall 2 MPG loss.
If the rear drive ratio is switched from 3.15 to 3.73, the PCM must be reprogrammed or shift points will be way off.
For road course driving I believe there is no need for anything but a stock torque converter.
It is not all about power, the 370Z was faster until he spun into the mud:
My C5 A4 had a 3.15 rear drive ratio but a bearing began shedding metal at Buttonwillow Raceway in 2016. Also found both Bellville springs broken in the differential. Switched to 3.73 rear drive ratio with a geared WaveTrac differential. The car is much faster on a road course with the 3.73 rear drive ratio and a differential that does not appreciably slip under high torque.
With the transmission in 4th, 75 mph is at about 2450 engine rpm, fine for cross country driving.
Going from 3.15 to 3.73 resulted in an overall 2 MPG loss.
If the rear drive ratio is switched from 3.15 to 3.73, the PCM must be reprogrammed or shift points will be way off.
For road course driving I believe there is no need for anything but a stock torque converter.
It is not all about power, the 370Z was faster until he spun into the mud:
What mods does your car have? So 3.73s will do 75mph at 2450 which is probably the highest you want on a street driven highway vehicle.
I just got my C5 back a few days ago from Speed Inc., Schaumburg IL. They did a RPM 373 and YankSS 3200 stall. I’m still in the brake in period and haven’t got on the peddle yet. As far as normal driving, Surprisingly converter feels like stock. Don’t need much gas to get it moving at all. RPM’s stay under 2200 under normal acceleration. I have a trans cooler and after about 45 minutes of driving when it’s 90 degrees outside, trans temp is 168-172. I really like the way it feels. I’ll post more information when I put my right foot through the floor. I also have about 2500 miles on the car of HPDE events, 3.15 gears and stock converter. Speed INC said I could probably road course the car still with 3200 converter, they said anything over the 3200 converter, the converter would be flashing to high pulling out of the corners.
From Justin: "What mods does your car have? So 3.73s will do 75mph at 2450 which is probably the highest you want on a street driven highway vehicle."
My car is Z51, has Bilstein Shocks as modified by Doug Rippie Motorsports, steel stabilizer bar connectors, B&M finned aluminum transmission pan with extra capacity, auxiliary transmission cooler in front of the condenser, DeWitts aluminum radiator with both engine oil and transmission fluid coolers, Improved Racing engine oil thermostat and braided SS oil lines to the radiator engine oil cooler. 3.73 rear drive with WaveTrac differential, Sac City Cool It with which I can call up high fan coming off track.
No horsepower mods.
On track the critical temperature to monitor is transmission temperature. Never an issue at Laguna Seca, but now at Arizona Motorsports Park in May after first or second session I decide to come off track a lap early when trans temp hits 250- probably conservative. Next season- a larger auxiliary cooler.
May 7, 2022 at AMP first session, I passed one car and no one passed me. OK for a 77 year old driving a 21 year old car.
I see the final gear ratio mph vs the standard c5 and z06 are different are the z06 c5 transmissions different from the standard c5 6 speed and not .050 overdrive? I see 1-2-3 are shorter gear ratio and od are shorter as well.
Last edited by Justin Raney; May 17, 2022 at 05:11 PM.
From Justin: "What mods does your car have? So 3.73s will do 75mph at 2450 which is probably the highest you want on a street driven highway vehicle."
My car is Z51, has Bilstein Shocks as modified by Doug Rippie Motorsports, steel stabilizer bar connectors, B&M finned aluminum transmission pan with extra capacity, auxiliary transmission cooler in front of the condenser, DeWitts aluminum radiator with both engine oil and transmission fluid coolers, Improved Racing engine oil thermostat and braided SS oil lines to the radiator engine oil cooler. 3.73 rear drive with WaveTrac differential, Sac City Cool It with which I can call up high fan coming off track.
No horsepower mods.
On track the critical temperature to monitor is transmission temperature. Never an issue at Laguna Seca, but now at Arizona Motorsports Park in May after first or second session I decide to come off track a lap early when trans temp hits 250- probably conservative. Next season- a larger auxiliary cooler.
May 7, 2022 at AMP first session, I passed one car and no one passed me. OK for a 77 year old driving a 21 year old car.
Nice to see sac city has a fan adjustment switch or thermostat to turn the fans on earlier then having to get a tune just for that. I once used the **** adjustment probe thermostat for fans to come on in a 66 fairlane and it worked i later just used a switch with key on/off.
I see 4.11s in the auto are 2500rpm vs 2300-2100. 3.73s-4.11 the way to go as 2nd is a long gear before drive but as the redline is 6200rpm or shift points itll be lacking mph and require good tires for street use. When it shifts to 2nd with 3.15s its a long dog 2k-6k i cant find any power till 5k rpm which im used to from having manual 6 speed cars 95z28 and 98 z28 both 6 speeds. This would make for 6 speed conversion or torque converter 3600 stahl good use i still think 5k rpms is the funner rpm range after having the auto get up that high. This will lose a race easy without a drag radial on the streets and the throttle floored.
I see the final gear ratio mph vs the standard c5 and z06 are different are the z06 c5 transmissions different from the standard c5 6 speed and not .050 overdrive? I see 1-2-3 are shorter gear ratio and od are shorter as well.
Yes the transmissions are different. That's why you see the gear ratio variance between the MN6 C5 and the M12 transmission equipped Z06 with the same 3.42 gear ratio.
The M12 in the Z06 with 3.42 gear is like the MN6 with a 3.90. Almost like for like on the RPM band.
I see 4.11s in the auto are 2500rpm vs 2300-2100. 3.73s-4.11 the way to go as 2nd is a long gear before drive but as the redline is 6200rpm or shift points itll be lacking mph and require good tires for street use. When it shifts to 2nd with 3.15s its a long dog 2k-6k i cant find any power till 5k rpm which im used to from having manual 6 speed cars 95z28 and 98 z28 both 6 speeds. This would make for 6 speed conversion or torque converter 3600 stahl good use i still think 5k rpms is the funner rpm range after having the auto get up that high. This will lose a race easy without a drag radial on the streets and the throttle floored.
You have a 220/224 elgin cam, assuming 112 lobe seperation? This is why your car is a dog at low to mid RPM with 3.15s in it. The car wants more gear for that cam.
Its actually pretty close to stock cam from idle if you ask me lol the cams somewhat small other vendors told me the biggest theyd go would be a 224/224 with the stock converter. Mines 1839 secret sauce x cam from elgin the stage 1.75 just above the stage 1 216/220 cam. If you ask me it feels about the same as the stock cam just you cant play with the shifter or gearing and drive the car as you would like a 6 speed 5k rpm - 6600rpm. If youd excuse me i think it makes about the same power atleast as the stock cam 2k rpm up it just doesnt really have the fun power im assuming this is with all autos till 5k rpm. Even with any auto the fun range wouldnt be till 4k rpms if you ask me it burns out real easy and gets sideways when you floor it but is dangerous when not manually gear controlled of a 6 speed with gear selection, clutch etc.
These are made for 4.8s-6.0s this is an ls1 im not ******* the cam im just saying without gears is similar to stock when cornering you cant clutch or taking off from a stop light simply floor it thru 1st gear into 2nd spinning. Itll break the tires loose 30-50mph when romped on i just see that the AUTO 2nd is that of a 6 speeds 2-3 gear and really long so its like missing 2nd gear. This is more of an auto vs 6 speed debate at this point.
It really is a 6 speed debate i see even a 2400-3600 stahl would only be used when fully floored with lock-up. When racing or driving my 95z28 with 4.10s 6 speed hooker shorts, k&n cai, flowmaster muffler the rev limiter is 5700 rpm the car was fun as you could put it in first and floor it all the way thru till shifting to second. The same with my 98z28 6 speed 375whp same but with ud pulley had 3.42s not 3.15s ran 114-116mph and 126mph-131mph with a 6-9lbs s475 in 80 degree-40degree midnite drag weather. For the 350whp/tq 99 c5 would need atleast 3.42s i think 4.11s would be great but as the tuner usually leaves the stock shift points and dangerous on the street without a drag radial. Its a great cam for use with the stock converter alot of the problems are just that associated with auto when trying to run it thru first gear. I have ran it one time 1-2-3 or manual shifted it and it was as fun as any other 6 speed car but i would tear up the wave rings.
I didnt calculate or put much thought into it as i thought backwards GM made a 6 speed and auto version of these cars and as my left arm injury i was suffering when looking for a vehicle i thought the auto would be more fun which it is nice to drive not having to shift every gear the cam runs that of stock cam NOT WORSE when barely driving and gets fairly good gas mileage. Im not ******* the cam but the auto is killer.
DONT BE HATING MY CAM THIS secret sauce x, tsp headers, volant oval air filter auto 3.15s as good as its going to get for an AUTO. I think 3.90s-4.11s would be great as its a weekend warrior daily driver.
If It were 6 speed id have opten for the elgin sloppy stage 2, clutch and speed enginnering headers with the 3" x pipe i wish i couldve gotten for the 99 c5 but were on backorder at the time i was looking for headers. I should've went with a jegs XHD 2800-3200 or 3600 stahl 10" 30 spline lock-up for 600hp.
I think 799s, 4.11s, UD pulley IF IT DOES AS 13hp as asp claims, ls6 intake or fast 102mm could maybe net 400whp. Im assuming the 799s add power thru all powerband as they were 4.8 5.3 trucks that use off idle towing and dont usually go above 4k rpm but i maybe wrong ive never seeen a dynograph from 2k rpm up of direct 243s,799 swap to see how much power was gained by simply the stock heads that flow 260cfm vs 225-230cfm the stock 853s flow.
FYI the car does drive like stock with the 1839 cam from idle and thru the gears just often youll find yourself caught in 2nd for a long time vs (6 speed 2-3 gear. By the way ive never owned auto performance vehicle is where alot of this comes from but it does make for a good daily driver with exhaust, cam sound and i think far superior to a stock exhaust, cam 99 c5 auto corvette but i maybe wrong.
Last edited by Justin Raney; May 17, 2022 at 07:11 PM.
My C5 A4 had a 3.15 rear drive ratio but a bearing began shedding metal at Buttonwillow Raceway in 2016. Also found both Bellville springs broken in the differential. Switched to 3.73 rear drive ratio with a geared WaveTrac differential. The car is much faster on a road course with the 3.73 rear drive ratio and a differential that does not appreciably slip under high torque.
With the transmission in 4th, 75 mph is at about 2450 engine rpm, fine for cross country driving.
Going from 3.15 to 3.73 resulted in an overall 2 MPG loss.
If the rear drive ratio is switched from 3.15 to 3.73, the PCM must be reprogrammed or shift points will be way off.
For road course driving I believe there is no need for anything but a stock torque converter.
It is not all about power, the 370Z was faster until he spun into the mud:
Get a transmission cooler. With the 373 gear and 3200 stall, mine hasn’t been over 172 degrees in 90 degree weather, but I’m also going very easy on the pedal, still breaking in the differential.
when I had the 3.15 gears/ stock converter and at HPDE event, transmission temps never hit over 205 degrees, and that’s beating on it hard. Get a cooler.
I think its more of an auto vs 6 speed debate with the long auto 2nd gear 4.11s would make a pretty good improvement over the 3.15s almost a 1/4 of gear ratio change 3.15s-4.11. Another thing is to run a 24" autocross hoosier drag raidal 245/17 would change the 3.15s with 26.1"-26.7" tire to 3.40-3.42 gear ratio for drag racing purposes.
The car already has a transmission cooler. Fluid temperature do not go up on the street, only after about 8 laps and 15-18 minutes of full throttle road course straights.
The car already has a transmission cooler. Fluid temperature do not go up on the street, only after about 8 laps and 15-18 minutes of full throttle road course straights.
I read somewhere transcoolers cooled the trans fluid temps by 30 degrees i saw on a summit racing website post regarding adding a transcooler. Will the standard tube transcooler function just as good as the thin plate expensive b&m coolers and are in terms of transcooler bigger is better? I like your style of transcooler which can be had for 40-80$ from summit or jegs hayden. Is it necessary to buy a pusher fan or will driving air temps cool it thru the stock air dam with the stock cooling fans. Is there an optimum temp for the trans fluid say 160-230 degrees before itll start melting seals at 260 degrees? Some people say 220 degrees is optimum for performance of that an ls1 engine when changing thermostats but i think a 180-160 degree thermostat would be better.
Nice you got the standard jegs or summit tube finned cooler and not the flatline plate transcooler? Any transcooler would work but is there a specific brand that is known to be bad or not good in terms of transcoolers on any vehicle. I see alot of people run the 220$ b&m transcooler with the thermostat that doesnt allow it to go thru the transcooler till it reaches a certain temp 180 degrees or so which allows the cars fluid to get up to operating temp.
When driving thru town the transmission fluid will get as hot as the cars coolant temp after an hour drive the trans temp will read 180-200 degrees just as hot as the coolant i had spoke with someone about transcoolers they had told me the radiator it passes thru already heats up the trans fluid and some either bypass or just run the transcooler inline now should the transcooler go before or after the trans fluid passes thru the radiator?
