Thread: RS5F70A trans with 4.4 FD for turbo... yes or no?

The car is at 303bhp/228lb.ft and traction is already an issue, should i go with the 4.4? Or would that be too much, and accentuate an already present problem?

I´m planing fitting a qdf17l Quaife LSD with it...

Would it be worth it? or is not that big of an improvement on a turbo car? Only worth on N/A? I´ve never driven a car with shorter FD, never experienced the before and after, so i don´t have a base for comparison, would be that noticeable?

Also, is the Phantom Grip "hack" worth consideration? The Quaife is pretty expensive...

Shorter gearing increases your usable torque, that's why it's ideal for N/A since N/A based builds tend to center around high power in high revs, not low-mid range power. Turbo as you know gives you more usable torque down low and in mid range... shorter gearing as you correctly guessed would absolutely accentuate the issue. If it were my choice, I'd avoid the 4.4

Try a stock p11 trans

i didn't think the 70a/v was available with a 4.4? always 4.176.

you could wait for the mfactory helical unit. like 1/2 the cost of a quaife.

No problem with shorter gearing. Depends what you aiming for...

Its stupid to think that shorter gearing is bad because of traction... its very easy, why to make power if you dont have traction?

LSD, good (semi)slick tires and you will be good.

A 300HP car should have no traction issues. Are you running it on Slicks and if so what size?

First of all sorry for not posting in the correct section apparently...



It is, at least in EUDM, also australia n16 hatch as the 4.4 diff, in fact it´s common, but not on SR20 guise, it´s present on QG16 primeras and QG18 Almeras... sr20 70a´s are pretty rare, almost everyone of them is CVT auto....



I am quite limited in budget, so i couldn´t afford a LSD and the stronger box, that´s why i have power with no traction, but by bits i´m getting there... one thing at a time...

I had semi slicks when i was n/a, Toyo R888 in 14" but unfortunatly i had to upgrade to 16" due to big brakes, in my opinion for a street car, where i live, semi slicks are stupid, you just can´t use them, the pavement is dirty, bumpy and the tyres just don´t grip, for a street car, good street tyres... that´s my opinion, but this is a discussion for another time... i really didn´t think it was worth it... too much noise, too stiff side wall and oyu need clean road to have grip...



As i said, no slicks, explained above, and i disagree with you, a 300bhp will have traction issues, even with LSD, just depends on circunstances...

Semi slicks for me are out of the question for several reasons...

Is just a car to have fun, i don´t drag and don´t plan to win races, just to have a laugh...

The M factory´s LSD is also out of the question, because of the shipping plus taxes and etc, i live in a country in deep crisis penalized with big big taxes, when that arrive to my hands it´s the same price of the quaife or even more expensive...

I´m still undecided if i´ll go the 4.4 route, since i´ll be opening the 70A to install the diff, and can get a 4.4 gearbox on the cheap locally... i´m afraid it would translate in more wheelspin for not much gain...

the hatch diff centre won't work dude, only the sedan. few people is aus been caught out trying this.

The diff center? That will be replaced with the Quaife LSD... the crown wheel is all equal right?

So what you sayin is that the driveshats don´t work? or the actual open diff is of a diferent size?

But regarding the crown wheel it is the same right?

I am so happy to see this section already getting used - Thanks @Vadim

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@groundscraper

I have been upgrading my B14 Turbo cars from their original B14 RS5F32V transmissions to the USDM P11 RS5F70V. The USDM P11 RS5F70V shares the same 4.176 Final Drive Ratio that the USDM B14 RS5F32V has. What you had previously mentioned is one of the reasons why I did not go with the USDM B15U RS5F70V Sentra as it has a 4.437 Final Drive Ratio.

If I still had to commute 1-1/2 hours to work every day then I would have gone with a RS6F51H box from a 2003 A33 Maxima which has a 3.812 Final Drive Radio. My reason for considering a RS6F51x box is so that I could travel at 80+ MPH at 3,000 or less RPM.

Using a 6 Speed box may better suit you needs, especially if you have access to the P11 Bell Housing.

The only real reason that I have not gone with a 6 Speed box is that I am not a big fan of cable shifting. I prefer the feeling of solid shift linkage.



The best suggestion that I can give to you is to first decide if this is going to be long term car project/relationship for you or not. If it is, then save your $$$ and get EXACTLY what you want and don't settle for anything less. Just keep in mind, these things don't happen every night. I have cars that I have been working on for over 20 years and they are still not where I want them to be.

Good Luck!