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Shop advertises rebuilt 5 speeds that can take 300+ hp. I feel like I read similar things about quaife, no? Has anyone dealt with them? I'm just super curious about this option because a 5 speed set up to handle 300ish hp for 1250-1500 sounds almost too good to be true. I wonder if they guarantee their work...
Interesting stuff, I've noticed some of what they talk about in the NB 5 speed I'm rebuilding. Though, it seems all of their strength upgrading is in going to hardened studs to replace the bolts that hold the whole trans together. I am dubious as to how much strength those really add. But then again, they are only claiming a ~30% increase, so that is maybe reasonable over stock.
This looks amazing but sounds way too good to be true. As I understand it the main weak point in the 5 speed trans is the lack of bracing on the casing not holding up to twisting and torsional loads under high torque output. It seems the only way this is directly addressed is using studs instead of bolts... I doubt the resolution is that easy.
I believe the Quaife was just an upgraded gear set and didn't really address the weakness in the casing.
We'd need someone like Sav or Emilio to really put it through its paces.
And nitrodann says you can run stock 6 speeds on the track at, what did he say, 360 horsepower without failing? Total bull. Claims are not worth a **** until you have backup. A sample size of a couple does not a solution make.
OEM case. no improvement. Its a big pile of lying to the masses. I think they are kind of just delaying failure with stronger gears.
somewhat unrelated,here is a transmission meant for big power. 11.5" r&p. Even a world class manufacturer wont rate this as a race transmission. still call it a trans for Hi-hp street legal buggies. strong boxes aint cheap.
PS, I got to drive a car with this trans backed by 600 hp. It was glorious banging gears without a clutch.
OEM case. no improvement. Its a big pile of lying to the masses.
Right? That was my first question. From everything I've read, case flex was the issue. I wonder if there's external or internal bracing that can be done there, but even so... I'm not sure how this all helps when case flex causes the kablooeys.
To be fair, most of the opinions on the cause of Miata 5 spd torque related failures are speculation. A specialist can identify the causes of failure that a non-specialist might miss. I have never seen any conclusive evidence that case flex is the sole factor in 5spd torque failures. Maybe it is.
Browsing through their site, I get the impression that he (they?) know what they are talking about. The claims of 300whp capacity for their stage 2 might be optimistic but my guess is that it does have a significantly raised capacity over an OEM rebuild. Curious to see what reports come in from the
Miataverse after a few folks try these boxes.
Links to people who have run this gearbox on the track with high-output engines?
I think this is what they really need. As Emilio said based on their site they do give the impression that they know what they are doing and are familiar with the Miata chassis on a grassroots motorsports level. So I don't doubt there is at least some merit to their claims, but they simply can't throw numbers like 300+hp out without providing some sort of reconcilable proof.
Show us the cars you guys run these in, the power they are making, and how they are using them.
Also, curious (if their methods actually work) if they could further strengthen the 6-speed as well.... Looks like one of their product photos has one hanging around int he background.
Thinking back to my VW days, Big turbos would spread the Transmission box open and allow the gears to shear, but the event left a lot of evidence. So, has anyone seen evidence of a 5 speed box cracking after a gear failure.? sheared mainshaft? less that round bearing bores?
I think they do say they are working on 6 speed enhancements on the site. We need data. If they are marketing to this community, they should be at least lurking here.
Since I started this thread, I might follow through and give them a call or drop them an email with a link to this thread to see if they'd like to chime in. I'm sure they want to protect their product and whatever innovation they've done, but it would be neat if they were able to give more info and/or evidence about the trans surviving with the added power.
They have been fairly forth coming on information on Facebook posts I've seen about their reasoning for their claims. They do have a degreed metallurgist on staff according to their post. They supposedly have been testing a few of their 300whp capable units on multiple cars, but nothing has been definitively shown yet. While I don't for see needing a 300whp capable 5 speed anytime soon, I am interested in the stud kit for a future 5 speed rebuild just for peace of mind.
They do work on 6 speeds for the NC's too. Not sure how much translates to the NB1/NB2/MSM variations. They have a few good options for improving their strength as well. I believe they are currently the ones building all the transmissions for the Spec MX-5 series (rental NCs)
01-03-2019, 02:32 PM
Another Transmission Option?
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