NitroDann's Long Awaited Garage Thread

little decks · Postby **little decks** » Tue Mar 19, 2013 11:22 pm

Yeah I've seen Dad rebuild RX7 boxes and MX5 boxes and the RX7 isnt a great deal stronger, Dad was looking at a tremec conversion but it was too expensive to engineer it properly and then got into the NC stuff anyway which has some more options out there to strengthen the thing up... the axles werent really a huge issue, it was more of having too much camber which every now and then screwed the CVs.... just get yourself an SE drive train to start off with, its much much cheaper and shouldnt be a huge problem, a lot of the issues that are had are related to pretty abusive driving like dumping the clutch and compression locking the thing with the good tyre... ive seen Dad do two 6 speeds side by side... one went in a car with a little over 220rwkw and the thing lasted over a year running michelin 17x225 r8b compound slicks on the rear... the other box went into a car running about 180rwkw with 16x205 in the same compound and wont last 2 meetings, so obviously if you are a bit more sympathetic on the machinery that isnt a problem...

little decks · Postby **little decks** » Tue Mar 19, 2013 11:31 pm

also... ive never understood how solid mounts make a difference? I've never asked many questions or anything but the gearbox is bolted to the block and not the chassis.. so it moves with the engine anyway, the rear is independent not a banjo and the diff isn't solid mounted... so its already designed to effectively almost float in unison, so if anything solid mounting would be detrimental... any bumps and vibrations to the car start stressing the driveline wouldn't they?

Black_Penguin · Postby **Black_Penguin** » Wed Mar 20, 2013 12:29 am

Me and my Dad also play with Lotus 7 replicas, a popular gearbox is the Toyota T50.
I've known guys to break these with a 16v 4AGE (around 100hp) on the street, I know of one behind a 300hp 3SGE in a slick-shod race car that has survived for many years.
Mechanical sympathy is key.

Postby **Boyracer** » Wed Mar 20, 2013 8:29 am

I have a SE diff conversion for sale.

gslender · Postby **gslender** » Thu Mar 21, 2013 9:58 am

little decks wrote:also... ive never understood how solid mounts make a difference? I've never asked many questions or anything but the gearbox is bolted to the block and not the chassis.. so it moves with the engine anyway, the rear is independent not a banjo and the diff isn't solid mounted... so its already designed to effectively almost float in unison, so if anything solid mounting would be detrimental... any bumps and vibrations to the car start stressing the driveline wouldn't they?

It stops torque twisting and fixes the changes in the gear selector, which if the seat and driver rotated with the engine/gearbox, then yes solid mounts wouldn't be needed.

G

little decks · Postby **little decks** » Thu Mar 21, 2013 4:04 pm

I understand that it stops torque twist but i kinda think solid mounts will do more harm than good, in regards to the gear selection... the box has synchros and is designed so that you dont have to put it in the right place, so long as you provide minimal force it will move across the gate where it needs to go from gear to gear, if you have problems with that its because you are forcing it to go where you think it should go and no amount of elbow grease will ever help the situation... just destroy your box... where you are seated relative to all this shouldnt matter the angular rotation of the gearbox in terms of degrees of rotation one couldnt imagine it would be more than 10 degrees

gslender · Postby **gslender** » Thu Mar 21, 2013 5:44 pm

little decks wrote:I understand that it stops torque twist but i kinda think solid mounts will do more harm than good, in regards to the gear selection... the box has synchros and is designed so that you dont have to put it in the right place, so long as you provide minimal force it will move across the gate where it needs to go from gear to gear, if you have problems with that its because you are forcing it to go where you think it should go and no amount of elbow grease will ever help the situation... just destroy your box... where you are seated relative to all this shouldnt matter the angular rotation of the gearbox in terms of degrees of rotation one couldnt imagine it would be more than 10 degrees

no. the issue is that under extreme torque acceleration you can accidently select 2nd->5th and miss 3rd gear because of the twisting that is occurring at precisely the same time the gear change is occurring. When you are racing you kinda want to avoid any subtle issues. many folks who have fitted them have reported less occurances of miss gear changes due to the gearbox/engine not torque as much. MazdaSpeed even sell stiffer mounts so I'm confident it is ok. Some people even fit solid mounts that are even stiffer still !!

little decks · Postby **little decks** » Thu Mar 21, 2013 10:48 pm

I understand what you are saying and I have experienced what you are talking myself, but once I was more comfortable in the car and more relaxed I wasn't trying to force the gears so much and then the twisting wasn't an issue for selecting gears... I can see how it would be more of a problem with a dog box though.

vrmmmpshhh · Postby **vrmmmpshhh** » Sat Mar 30, 2013 1:15 am

newly installed setup courtesy of dann.. hardest part of the install was the dump pipe, the compressor housing has to be removed for the dump pipe to squeeze out of the car.

16bit · Postby **16bit** » Sat Mar 30, 2013 8:34 am

what would the boost limit be to stop the o2 sensor burning out?

Postby **NitroDann** » Thu Apr 04, 2013 8:12 pm

I imagine its only in there for tuning.

Dann

Postby **NitroDann** » Thu Apr 04, 2013 8:13 pm

Livin' the roadster life. :roll:

Dann

little decks · Postby **little decks** » Thu Apr 04, 2013 10:58 pm

Are just match porting? or going for some shape?

Postby **NitroDann** » Thu Apr 04, 2013 11:09 pm

Matched, and took the ridges and casting marks out, thinned the walls between the ports a little and took some of the 'belly' out of the sides of the port walls where the castings get bumpy close to the valves, also had soft valve seats so took the lip off the back of them.

Big improvement, but unlikely to help in stock form at all, would be likely to need boost to see gains. Time will tell.

Dann

little decks · Postby **little decks** » Thu Apr 04, 2013 11:13 pm

I've seen Dad try 4 or 5 different porting combinations over the years doing 2F engines and it can make a huge difference on an NA car... but when its boosted i've seen him get around 20-30rwkw at the same boost.

Edit: I would try sussing out someone with some experience in porting drag racing cylinder heads... and do you have access to a flow bench?