Go a 5 speed Supra , or a 3.08 Diff

**Cyclamin** · 20-05-2014, 12:22 AM

Have the opportunity to get a 5 speed supra box with all the bits to fit it. Cost will come in around the $1,500 mark , or just refit the diff with a 3.08 ratio (Currently the GV7 3.55 ratio) at a lot lower cost. Motor is a slightly tweaked 253.
Question is , go the Supra , or change the ratio ??
Any comment would be appreciated..
Cheers

**Valencia** · 20-05-2014, 12:40 AM

Change the ratio but if your doing long drives both would be good

**Frosty** · 20-05-2014, 12:55 AM

I have a 253 with a 3.08 and every time I get to 80km I look for 5th. Definately both. Come for a drive and you will agree.

**Cyclamin** · 20-05-2014, 01:39 AM

Hey Frosty, Thats similar to mine , what kph at 3,000 rpm , mine is around 110 - 115.

**Frosty** · 20-05-2014, 02:57 PM

Originally Posted by Cyclamin

Hey Frosty, Thats similar to mine , what kph at 3,000 rpm , mine is around 110 - 115.

I didn't know the answer to that so I took a drive. 3000 RPM=108 kph in 4th. (speedo and GPS). I believe my van has a 3.08 as the previous owner told me that is what she put in,but I have not had it out to confirm. On a curious note, I then checked my Triton ute on the way to work and it to in 4th gear at 3000 RPM was also 108 kph. At 3000 in 5th it was 132 kph, nearly blew my beanie off. Better still at 2000 RPM it was 90 kph. I wonder if the 5th gear ratio in the Celica is similar?

**Cyclamin** · 21-05-2014, 10:59 AM

Hmmm , might try the GPS trick with mine on the weekend. Sounds like we may have the same ratio's , just not sure which one??

**Frosty** · 21-05-2014, 11:28 AM

I do believe that my diff is 3.08 as other things I've reed support that. Sounds like you may already have a 3.08. The yellow needle on the dash can be a bit vague, GPS is better.
I think you should put in the Celica box and let me know how it goes.

**panoz78** · 22-05-2014, 02:47 AM

If your running at around 105 @ 3000rpm you have a 3.55 ratio diff .
I've had mine out and defiantly know my ratio,
If you want to check jack it up ,put a mark on the yoke & housing then turn your wheel one turn,
count the revolutions of the tail shaft, 3 1/2 turns 3.55 ..approx 3 and a bit 3.08 .
You could also try different profile tyre eg. 50'series- 60's ,or even larger rim size 14-15's will drop your revs as well
The summit site have a few calculators you could play with as well

http://www.summitracing.com/expertad...mission-lookup

http://www.summitracing.com/expertad...tio-calculator