help

oddeecius · 05-21-2008, 12:28 AM

hi i just bought a 1991 mr2 non turbo and i was wondering if there is a way to swap the transmission out. can anyone help?
sorry i have the 5 speed but at 3000 rpm im only going about 55 mph at 5th gear. i was wondering if there is a kit that will lower the gear ratio slightly for my mr2
my car is lowered with 17 inch wheels and everything else is stock

Ku-sama · 05-21-2008, 12:30 AM

you can easily swap the tranny. just stick with a 5S tranny because the gearing is meant for lower power.

sickof5sfe · 05-21-2008, 12:31 AM

swap the tranny out for what? a new one? a turbo one? Auto- manual? more info..

SpeedySix · 05-21-2008, 09:15 AM

Quote:

Originally Posted by oddeecius

hi i just bought a 1991 mr2 non turbo and i was wondering if there is a way to swap the transmission out. can anyone help?
sorry i have the 5 speed but at 3000 rpm im only going about 55 mph at 5th gear. i was wondering if there is a kit that will lower the gear ratio slightly for my mr2
my car is lowered with 17 inch wheels and everything else is stock

It sounds like what he is talking about is trying to get better fuel economy. He says 5th so you know it is a manual transmission.

The short answer is no. There is no kit. If you could find a final drive ratio from a 94+ s54 transmission out of a JDM MR2 (That would be an MR2 with a 3rd gen 3S-GE) you could replace yours and get better gas milage. However, if you were to replace your whole transmission with one of these later ones, you'll find that you will not have as much power in the other gears as several of the gear ratios change.

Another thing to remember is that you have a manual, not an automatic, so your RPMs are going to be higher a lot of the time, but that doesn't always mean you are burning more gas. Sometimes going at lower RPMs and trying to make the car do more work than the power allows gets you worse fuel economy and puts more stress on the engine, so your RPMs don't always tell the full story.

If you are interested in going with a gen 3 3S-GE transmission, the last time I talked to Josh at Chico Race Works (a board sponsor) he had several of them in stock. I'd recommend trying there.

oddeecius · 05-21-2008, 03:58 PM

i was wondering if the six speed from the celica can fit my car.
if it can can i swap the gears out from my old and put it in the 6 speed but leave the 6th the way it is.
im more of a 4x4 fan but i love the mr2 and i want to uprgrade it the way i upgrade my truck so any help with the car will help.

sickof5sfe · 05-21-2008, 05:12 PM

You can't without extreme fab work...and that is a fairly weak tranny anyways so it wouldnt be worth it. And upgrading an MR2 is fairly different than a 4x4 truck so its gonna take a bit of time to get used to what upgrades are gonna provide decent results and which ones are gonna be complete wastes of time and money

SpeedySix · 05-21-2008, 05:40 PM

Don't do it. There will be a ton of work for no reward at all. The 5 speed is already geared for the engine. Just leave it the way it is, or put a taller final drive in.

Everything that applies to this thread would apply to you if you want a 6 speed.

6spd for the 3sgte in mr2

bumpstickboogie · 05-21-2008, 09:55 PM

rpm's have little to do with gas mileage. gas mileage is mainly about load, or how much energy it takes to maintain whatever speed your going. also cruising at less rpms isn't really benefitial to your engine either, and your car will not be very fast with tall gears.

Gairloch · 05-21-2008, 11:33 PM

To answer your question the best way of changing the gear ratios and final drive in an s54 (mk II na transmission) is to swap out gears and final drive from an s51 out of a celica or camry.

Transmission Gearing Calculation Charts

That being said, what is it you're trying to solve? Even with the engine revving to 4k rpm at 70mph I still have gotten 30+ mpg on road trips. If you're getting poor fuel milage it's not because of the engine revving.

mr220v · 06-02-2008, 04:23 PM

^yeah, the stock setup gets good fuel economy at 4000rpms, but I'm thinking that there's 4-5mpg to be had by dropping it down 500rpms or so.

bumpstickboogie · 06-02-2008, 09:03 PM

Quote:

Originally Posted by mr220v

^yeah, the stock setup gets good fuel economy at 4000rpms, but I'm thinking that there's 4-5mpg to be had by dropping it down 500rpms or so.

the engine would still need to produce the same amount of power to maintain whatever speed you are going, and i don't think rpms are a big factor in the efficiency of converting fuel into mechanical energy. the biggest problem is that fuel injection is so fast and doesn't allow the fuel to atomize very well, so i guess it can't hurt to slow the engine down.

mr220v · 06-03-2008, 10:00 AM

If rpms didn't matter, then I could cruise at 80mph in 4th gear and still expect 30mpg.

I remember driving an automatic ford escort that wouldn't get out of 2nd gear. I could barely make 45mph. I drove this car for maybe 8 miles. By the end, the gas gauge had dropped a third of a tank.

The cars that have the s51 tend to get a bit better gas mileage than the mr2 does, even though they weigh the same.

If the s51 5th gear set would fit in an s54, it would make a 8-10mph difference. Playing with that gear ratio calculator, at 80mph, you'd be turning 3500rpms.

Servin · 06-03-2008, 02:31 PM

^It does swap in. That or you can take the taller FD from a euro N/A they have the 3.94 FD. Though with that youll lose some of the that oomph the 5SFE has in 5th and you might have to down shift instead of just stepping on the gas.

mr220v · 06-05-2008, 10:36 AM

I think I like the 5th gear option best.

1. The parts to do the 5th gear are cheaper, and easier to get.

2. It should be more of a drop in 5th gear rpms than switching to a 3.94 FD. 2/3rd's of the s51's advantage comes from the 5th gear and not the FD.

3. I can most likely get at the 5th gear components without taking the transmission out of the car. On a mk1 I had years ago, I was able to access the 5th gear stuff by simply taking off the tranny endcap while the transmission was in the car. Now, the mk2 doesn't quite give clearance to do this, but it might be possible if the 3 tranny mounts were removed. This would drop that side of the motor down. Removing those 3 mounts is easy enough.

05-21-2008, 12:28 AM	#1 (permalink)
oddeecius No Skills Join Date: May 2008 Location: CALIFORNIA Posts: 4 Thanks: 2 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	help hi i just bought a 1991 mr2 non turbo and i was wondering if there is a way to swap the transmission out. can anyone help? sorry i have the 5 speed but at 3000 rpm im only going about 55 mph at 5th gear. i was wondering if there is a kit that will lower the gear ratio slightly for my mr2 my car is lowered with 17 inch wheels and everything else is stock Last edited by oddeecius; 05-21-2008 at 12:37 AM. Reason: not enough info

05-21-2008, 11:33 PM	#9 (permalink)
Gairloch Dreaming of apexes Join Date: Aug 2005 Location: Minneapolis, MN Posts: 4,426 Thanks: 114 Thanked 219 Times in 192 Posts My Google Map iTrader Rating: (7/100% )	To answer your question the best way of changing the gear ratios and final drive in an s54 (mk II na transmission) is to swap out gears and final drive from an s51 out of a celica or camry. Transmission Gearing Calculation Charts That being said, what is it you're trying to solve? Even with the engine revving to 4k rpm at 70mph I still have gotten 30+ mpg on road trips. If you're getting poor fuel milage it's not because of the engine revving. __________________ "Inside the car, the world beyond the driver's immediate horizon ceases to exist. Alone with the solitude of his desire, survival sense numbed by the speed, he's outrun the mediocrity of the outside world, slipped the shackles it tries to clamp on us all. He is running free, chased only by a fear of failure, for failure is to risk ejection into the real world." ~Mark Hughes

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05-21-2008, 12:30 AM	#2 (permalink)
Ku-sama Cage Fighter Join Date: Mar 2008 Location: Bowie Maryland Posts: 902 Thanks: 6 Thanked 20 Times in 20 Posts My Google Map iTrader Rating: (2/100% )	you can easily swap the tranny. just stick with a 5S tranny because the gearing is meant for lower power.

05-21-2008, 12:31 AM	#3 (permalink)
sickof5sfe doing a secret build >:D Join Date: Jul 2007 Location: Richfield Minnesota Posts: 355 Thanks: 11 Thanked 3 Times in 3 Posts iTrader Rating: (1/100% )	swap the tranny out for what? a new one? a turbo one? Auto- manual? more info..

05-21-2008, 03:58 PM	#5 (permalink)
oddeecius No Skills Join Date: May 2008 Location: CALIFORNIA Posts: 4 Thanks: 2 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	i was wondering if the six speed from the celica can fit my car. if it can can i swap the gears out from my old and put it in the 6 speed but leave the 6th the way it is. im more of a 4x4 fan but i love the mr2 and i want to uprgrade it the way i upgrade my truck so any help with the car will help.

05-21-2008, 05:12 PM	#6 (permalink)
sickof5sfe doing a secret build >:D Join Date: Jul 2007 Location: Richfield Minnesota Posts: 355 Thanks: 11 Thanked 3 Times in 3 Posts iTrader Rating: (1/100% )	You can't without extreme fab work...and that is a fairly weak tranny anyways so it wouldnt be worth it. And upgrading an MR2 is fairly different than a 4x4 truck so its gonna take a bit of time to get used to what upgrades are gonna provide decent results and which ones are gonna be complete wastes of time and money

05-21-2008, 05:40 PM	#7 (permalink)
SpeedySix Some Skills Join Date: Mar 2008 Location: Rockford, IL USA Posts: 78 Thanks: 6 Thanked 6 Times in 6 Posts iTrader Rating: (1/100% )	Don't do it. There will be a ton of work for no reward at all. The 5 speed is already geared for the engine. Just leave it the way it is, or put a taller final drive in. Everything that applies to this thread would apply to you if you want a 6 speed. 6spd for the 3sgte in mr2

05-21-2008, 09:55 PM	#8 (permalink)
bumpstickboogie No Skills Join Date: May 2008 Posts: 37 Thanks: 0 Thanked 1 Time in 1 Post iTrader Rating: (0/0% )	rpm's have little to do with gas mileage. gas mileage is mainly about load, or how much energy it takes to maintain whatever speed your going. also cruising at less rpms isn't really benefitial to your engine either, and your car will not be very fast with tall gears.

06-02-2008, 04:23 PM	#10 (permalink)
mr220v Beams Owners Group Join Date: Mar 2006 Posts: 1,255 Thanks: 13 Thanked 90 Times in 76 Posts iTrader Rating: (7/100% )	^yeah, the stock setup gets good fuel economy at 4000rpms, but I'm thinking that there's 4-5mpg to be had by dropping it down 500rpms or so.

06-03-2008, 10:00 AM	#12 (permalink)
mr220v Beams Owners Group Join Date: Mar 2006 Posts: 1,255 Thanks: 13 Thanked 90 Times in 76 Posts iTrader Rating: (7/100% )	If rpms didn't matter, then I could cruise at 80mph in 4th gear and still expect 30mpg. I remember driving an automatic ford escort that wouldn't get out of 2nd gear. I could barely make 45mph. I drove this car for maybe 8 miles. By the end, the gas gauge had dropped a third of a tank. The cars that have the s51 tend to get a bit better gas mileage than the mr2 does, even though they weigh the same. If the s51 5th gear set would fit in an s54, it would make a 8-10mph difference. Playing with that gear ratio calculator, at 80mph, you'd be turning 3500rpms.

06-03-2008, 02:31 PM	#13 (permalink)
Servin Cage Fighter Join Date: Aug 2007 Location: DFW, Texas Posts: 417 Thanks: 6 Thanked 25 Times in 19 Posts iTrader Rating: (1/100% )	^It does swap in. That or you can take the taller FD from a euro N/A they have the 3.94 FD. Though with that youll lose some of the that oomph the 5SFE has in 5th and you might have to down shift instead of just stepping on the gas.

06-05-2008, 10:36 AM	#14 (permalink)
mr220v Beams Owners Group Join Date: Mar 2006 Posts: 1,255 Thanks: 13 Thanked 90 Times in 76 Posts iTrader Rating: (7/100% )	I think I like the 5th gear option best. 1. The parts to do the 5th gear are cheaper, and easier to get. 2. It should be more of a drop in 5th gear rpms than switching to a 3.94 FD. 2/3rd's of the s51's advantage comes from the 5th gear and not the FD. 3. I can most likely get at the 5th gear components without taking the transmission out of the car. On a mk1 I had years ago, I was able to access the 5th gear stuff by simply taking off the tranny endcap while the transmission was in the car. Now, the mk2 doesn't quite give clearance to do this, but it might be possible if the 3 tranny mounts were removed. This would drop that side of the motor down. Removing those 3 mounts is easy enough.