Fortin 5 Speed - How many horsies?

[redmist]

Bit of background. I have a Jimco single seater coming into the country (NZ) within the next week. Its due to land without engine and I have a Nissan v6 3.5 ltr ready to plant in its belly (its a middy). In New Zealand we have no restrictions in regards to engine modifications for class 1 and some of the faster cars are running forced induction. The Nissan engine is reasonably easy to turbocharge and mid 400's are readily available without having to decompress the engine.
My question is simple... I know I'm pushing it... but will the Fortin 5 speed handle 450 odd hp? Or will I simply destroy the box?

Cheers in advance, Daniel.
Red Mist Racing
New Zealand.

[SPONSOR]

Membership in the largest desert racing community has its advantages - Participate in Forum Discussions - Send and Receive Private Messages - Maintain Public Photo Albums - Access to Groups - User Profile in our Social Network - Increased Access to more Sub Forums - Reduced Online Advertisements Join our community today

[cogbox]

is the trans a real fortin or is it a hewland box built by fortin? if it is a real fortin and you drive not like your seat is on fire, the trans will do just fine. but like all gearboxes if you beat them they will break. if you have a hewland gearbox save your money because it is quite old and will need service with that much horsepower going thru it. best not to use that trans, save up and get the real fortin. hope this helps

[redmist]

Its a genuine Fortin casing, however the older non ribbed version, regularly serviced. I dont know if I trust such a small box when the larger Albins boxes, Mendeola Sequential's are regularly destroyed with similar power.

[desertracer]

We ran the 5 speed fortin in our class 1 with a Northstar V-8, 400hp, 35'' tires with no problems. It was serviced every 1000 miles or less and it did wear gears but there were not failures. When we changed to an LS2 for power, switched out the trans for the wide gear 4 speed fortin.

[Superfab]

Seems like one of the biggest breakage factors is the drivers ability to shift properly especially on the down shift. Some people can kill a trans with low hp and others can run a high hp package with no problems at all. Some have gone to the converter to soften the shock loads on the drivetrain but this requires some hefty fluid coolers and the smarts not to lug it, slip the converter and bake the fluid.

[redmist]

Seems like one of the biggest breakage factors is the drivers ability to shift properly especially on the down shift. Some people can kill a trans with low hp and others can run a high hp package with no problems at all. Some have gone to the converter to soften the shock loads on the drivetrain but this requires some hefty fluid coolers and the smarts not to lug it, slip the converter and bake the fluid.

So any tricks to downshifting? I can see me breaking the box on a regular occurance. I've heard many techniques to shifting a race dog box. Everything from rev matching, to crashing it hard, to double declutching.

[Superfab]

The biggest sin is to try to punch it into a lower gear with too much rpm's. Rev matching is a must to keep from chewing up the dog faces and it helps to have the rpm's down enough so the loads aren't so great and is a bit easier to get the engine revs closer. It doesn't hurt to use the clutch for downshifting. Might just save you a few parts.