BGH vs. SPC?

[TurboWood]

Hi Guys,

I'm trying to narrow in on a transmission. From what I can tell the 5-spd is my best bet with any of the 2L engines (plenty of torque). I've read quite a bit about the BGH transmission, but haven't heard much about the SPC 5-spd. Do any of you have any experience? The gearing on the SPC unit should allow me to just touch 60mph in first if I can spin the engine to 7500rpm. All else being equal that would probably be enough to sway me.

 

Thanks,

Daniel

 

reference:

http://www.spcomponents.co.uk/index.html

http://bghgeartech.co.uk/html/5_speed.html

[anthonyseven]

My old Birkin had the SPC gearbox and a 2L Zetec on Jenvey throttle bodies. I thought it was fantastic.

 

Some folks complained that 1st was a bit tall for street driving. My Birkin had the 4.11 rear end and I didn't think it was uncomfortable at all; however, I never drove it in stop-and-go traffic.

[TurboWood]

It's probably worth mentioning I'll have a 3.38 final drive ratio. I do know of at least one guy that used a BGH transmission and 3.14 final drive. This would be almost exactly the same in first gear as a 3.38 and SPC. That makes me think it's manageable.

 

It just seems there are fewer people that used the SPC transmission. It's good to hear you liked it.

 

Daniel

[jlumba81]

I just received a long (2.74) 1st gear from SPC last week. Haven't gotten around to installing it. SPC you can contact them by email, but BGH is old school and you'll need to call them by phone. You can also buy Trans X and Quaife gearboxes thru Burton and Seven Speed carries BGH gearboxes. I think there are more BGH gearboxes on this forum than SPC.

[maurice1]

Hi Daniel

I have had a BGH 5 speed T9 Ford gearbox in my Birkin for the past 15000 miles. I have the 2.0 litre Duratec fitted and am running a 4.1 ratio diff.

The BGH kit fitted is the clubman spec which has a taller first approx 2.6 instead of the standard 3.0+ first gear ratio.

I have had no problems with the gearbox. Even with the taller first gear fitted i only use first when doing a hill start. I have friends who are running the same gearkit with a 3.9 diff ratio and it works ok.

I find if I want to do a fast takeoff from lights etc that 2nd gear works very well with the 4.1 diff, no revs drop off and no gear change between 1st and 2nd to slow you down. I know when my friend with the 3.9 diff did this on a 2nd gear high rev take off he stripped one of his pinion gears in the diff!!!

My engine is standard ford spec so only about 160hp and reaches the redline in 5th about 115mph quiet easily.

If you start going into taller diffs you may start loosing some of your acceleration and thats one of the great abilities of a 7. A taller diff may give you a higher top speed but 7s are aerodynamic bricks and need a lot of power to keep punching to a high top speed.

Choice is yours.

Cheers

Edited August 26, 2013 by maurice1

[TurboWood]

maurice,

This is really good information. I assume you have a 1.75:1 second gear?

 

1.75 x 4.1 = 7.175

2.482 (SPC 1st) x 3.38 = 8.389

 

From this it tells me starting in 1st with the SPC transmission shouldn't be an issue (I'll try to park on hills nose down).

 

Per my calculations I'll still be able to achieve 1g acceleration in 2nd gear which may be difficult for the tires to cope with. I think it will scoot just fine .

 

Daniel

[maurice1]

Hi Daniel

Yes 2nd gear is around 1.7/1.75

Cheers

Maurice