4.7 s4c too short for 270hp turbo b16b?


jesse888

jesse888

Ek9+Turbo+Nurburgring= Heaven
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As above,
Looks highly likely I'm going to end up with another ek9. The one I'll be buying has an s4c with 4.7fd. Do we think this gearing is too short for the above hp goal?
With a slightly raised limiter the top speed is almost unchanged. I'm worried about getting too much wheel spin from 2nd/3rd and pos 4th as these are the gears I use on most corners on track and really don't want uncontrollable wheel spin.
Torque would be roughly 175ftlbs.
Will have sticky track rubber probably 205 width.
Plate LSD aswell.
 
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Id say, you would be changing gear every second. Whats the new car your buying mate? Shaunek9's by any chance lol
 
Nah not his car. I'll be doing the conversion if it all goes through.
I put an offer in on Shaun's car but he hasn't come back to me. Working the power/ton out between a full fat 270hp turbo (roughly 1150kg after turbo conversion) ek9 and my old b18 track spec the hp/ton is only 35-40 extra with the turbo'd 9. I had a 4.9 on the b18 so I recon I could get away with it with careful throttle foot/gear selection.
 
jesse888 said:
Nah not his car. I'll be doing the conversion if it all goes through.
I put an offer in on Shaun's car but he hasn't come back to me. Working the power/ton out between a full fat 270hp turbo (roughly 1150kg after turbo conversion) ek9 and my old b18 track spec the hp/ton is only 35-40 extra with the turbo'd 9. I had a 4.9 on the b18 so I recon I could get away with it with careful throttle foot/gear selection.
Click to expand...

Id go with a 4.4 or get a s9b from the mb6 but that has stupidly long ratios. Boost and track, thats not going to be as fun round the bends. K20 problem solved boost is for pussy's lool😂
 
See what your saying, I don't want the gears too long either. Looking to gear the car towards the ring. With b18 I was hitting the limiter in 5th on 4.9 fd, stock limiter.
I would have thought 3rd would have full traction with only 175ftlbs? 1st/2nd arent used on track with an s4c anyway.
 
If you ended up needing a 4.4 I have a spare box I could take it out of. Think the 4.7 would be just that bit short
 
I have a friend with a 4.4fd box should I need it, assuming he doesn't sell it in the time I've done the conversion.
 
Just to add, if your aiming for 270bhp then you will have a higher torque figure than 175lbsft. Id say 200 minimum. Depends on the setup etc obviously.
For reference i had 165 lbsft on my b16 with only 6psi. That made 230hp

Murray
 
I don't reckon you need a particularly low gearset cos of the amount of torque you'll get. I suppose it depends where its made in the revs.....
 
Similar spec car on here. Scottek iirc has a turbo b16b and makes 268hp 175ftlbs at 7 psi. So that's where my 175 figure has come from.
Lots of people claim good traction with over 300hp but time will tell I suppose.
 
Use your standard ek9 gearbox, I have no problem with my turbo 9 and yes you have to regulate the throttle a bit when going round corners but that makes it more fun. I would advise on decent suspension as having the turbo kit adds to the weight on the front end. Im running 24kg spring rate on the fronts and 18kg spring rate at the rear to compensate the extra weight but thats on track suspension only as its no good for road use.
 
It's got a decent chassis on it already, the reason I'm wanting it tbh.
The box has a plate LSD in, so that's half the reason I'm wanting to make this box work with the power/torque.
 
Loveland aren't you at like 400hp?
 
I'd personally give it a go and you'll see. Swapping either the diff to a new box if there are any issues with the current one, or swapping the FD is not difficult. Plus you'll always be able to PX the 4.7 for a 4.4, much easier than the other way round. Shame you're so far, I have a couple spare LSD S4Cs so you could just swap the box and try it out...
 
Yeah I think it's going to be a trial and error thing. Most are thinking its alittle short while I'm on the fence. Suppose it would mean that I could back down the hp goal to gain traction. Saving the engine some stress at the same time.
 
I ran the standard ek9 gearbox for over a year with the car making 450bhp. Until One of the baffles in the the box decided to come off and messed up my final drive. Switched to the s9b gearbox after hated it. Now running a 98 spec s80 gearbox with a 4.7fd and its amazing!
 
How's the traction lol can't see it being great in 3rd? Bet 5th is like an n/a b series in 2nd lol
So you'd say go with the 4.7 s4c?
 
I run boost by gear and also 225 wide r888s now, so traction isnt to much of an issue it just hooks and goes! I would give the s4c with the 4.7fd a go. Worst hing your going to have to do is change it to a 4.4fd :nice:
 
You on 15" wheels? What wheels are they?
Boost by gear is another option. With an apexi boost controller or something.
 
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