Hi Gents,
I'm working on putting together a 7 and have settled on the type 9, but I'm not sure which vendor has the strongest/best build. BGH and SPC
are the two I've found (are there others?) and they offer similarly priced and named (HD) transmissions. Does anyone have any experience of one
being better than the other? I'm a little partial to the SPC since I should be able to hit 60mph in first gear at 7500rpm, but I'm also
unsure if first will be too long with my 3.38:1 final drive. Any advice would be great.
Thanks,
Daniel
3.38 is long unless you have a bike engine
Most use 3.6 and 3.9
If using on the road a very close box can be a compromise
BGH will fit any gear ratios a d attend a lot of kit car show
Other suppliers are Quaife and Elite
Not too sure 60 in first gear is making the best use of your power, it will have to be very high, I would have thought aiming for 70 in second would be closure to an ideal.
I have a BGH box in the car and a SPC box as a spare. Both are nice companies to deal with. Had problems with 2 BGH boxes that were replaced FOC, not
used the SPC one yet but I bought a diff from SPC in 1998,still in the car, quiet and leak free. What I have said to most people in the past is go to
the closest one, handy if you have issues. BGH is 200 miles for me, SPC less than 100 miles.
Now for my technical feelings.
If you are considering one of the "expensive" boxes SPC is IMHO without doubt the best.
SPC use ALL new gears in their boxes including a new lay shaft assembly. BGH use a new lay assembly but use reclaimed gears on the
mainshaft.
SPC use needle rollers on 1st and 2nd gears, makes a big difference to gearchange quality at full chat and the gears also have a far easier life at
high revs, in a BGH box they run directly on the mainshaft like a standard production box.
SPC use all new syncros, BGH clean up used syncros if they look OK.
On the budget boxes (the ones where they change 1st and sometimes 5th) SPC still use new syncros and the prices are lower.
snapper,
I would think bike engines would actually be worse since they have lower reciprocating inertia at idle. In other discussions I've had some cat
owners tell me the 3.62 with cat 6spd transmission was shorter than needed (off the track). I also know of at least one guy with a BGH 5spd and 3.14
final drive that uses the car on the street (Duratec 2.3L). Of course each person may have a different tolerance or idea of ideal.
zetec,
I'm shooting for 300-350hp (turbo 4). From my calculations I'll be able to accelerate well over 1g in first gear which is almost surely more
than the tires can handle. My biggest concern is just the driveability from a stop. I don't want to start a clutch burning business.
Paul,
Thanks for the feedback! That's the first b2b information I've found. I am more interested in the HD boxes in order to handle the power. As
i'm in the US neither supplier is super convenient. There just aren't many options in the US for the type 9.
Daniel
i run s spc gearset on my zetec turbo engine, long first gear revving to 8k
i run between 250 and 350bhp with no issues
beaver,
Do you have any pictures of you engine bay? I haven't come across too many turbo 7's. Do you have a dyno chart? Do you use the car on the
track?
Thanks,
Daniel
quote:
Originally posted by snapper
3.38 is long unless you have a bike engine
Most use 3.6 and 3.9
If using on the road a very close box can be a compromise
BGH will fit any gear ratios a d attend a lot of kit car show
Other suppliers are Quaife and Elite
Having had a Seven now for 25 years my personal opinion is the cars are all about rapid in gear acceleration for overtaking. A decent top for
reasonable cruising is also required but in mine with a 3.9 diff it is doing 3500 rpm at 70 which is fine (although higher than many tintops).
If you fit a 3.14 diff with either a SPC or BGH box you will end up with a car that will theoretically do about 58 mph in first at 7000 rpm (depending
on tyre size) and have a theoretical top speed of approx 175 mph. Such a high first gear will put quite a strain on the clutch. In a light car like a
Seven its normally the tyres that break traction in the lower gears before the clutch slips unless the clutch is knackered.
Based on my personal experience I would not want a turbo in a Seven ever. Driven a supercharged car once, did not suit the character of the car. With
175 bhp and a weight of about 600kg my car will beat almost anything on the road and does not frighten me. It had 208 bhp at one time but on a normal
road trip the car was no faster, it just used more fuel. I do not have to worry about the turbo coming on boost and throwing me off the road.
There are many Seven owners out there with 1.3 pushrods who have more fun than those with stupid power levels.
Just my opinion.
quote:
Originally posted by TurboWood
beaver,
Do you have any pictures of you engine bay? I haven't come across too many turbo 7's. Do you have a dyno chart? Do you use the car on the track?
Thanks,
Daniel
Thanks again guys, this is the exact conversation I was looking for since I have very little practical experience with a 7. My car will be used
primarily as a road going car, but I do look forward some track time. Hopefully I can find someone that has beat the SPC transmission hard enough to
know how its limits compare to the BGH.
laptoprob,
Your advice is sound. Attached is an estimated accel curve for the SPC transmission and 3.38 rear end. This includes an assumption for drag and shows
speeds close to what you had mentioned. For me 5th gear is really just for cruising so the top speed is irrelevant. 4th tops out around 140-150 which
as you pointed out is already crazy fast for these cars. For me it really does come down to if it will be manageable on the street or not. I may just
have to avoid the light weight flywheel/clutch. I think it's time to do some math on inertia to find out how this compares to other cars
I've driven.
Paul,
I agree the 3.14 is very aggressive. I'm only aware of one gentleman that has it (with BGH). I'm starting with the 3.38 and trying to figure
out if it will be reasonable with either the BGH or SPC transmission. I can always change later. Your comments about the turbo are interesting. You
aren't the first person to heed this warning. I can certainly understand the appeal of a predictable response. Turbos are just my thing and I am
putting an emphasis on transient response over ultimate power. Keep in mind modern 2L turbo engines are making 300hp from the factory (355 in the case
of AMG). Obviously I won't be buying a not-yet-released Merc, but it tells me the technology exists for a driveable turbo engine.
bearver,
Thanks and nice looking car! It's definitely a tight fit. It will be interesting to hear how the SPC transmission holds up and to see how much
power you can sustain on track before temperatures start to rise. The oil cooler is going to be working hard. I was thinking of running a more
conservative boost level on track for this very reason.
Regards,
Daniel
it is tight, i see oil temp of 105 after hard use on the road, thats laps on full boost on the dual carriageway
no doubt it would be higher on track but by how much i cannot tell you yet
quote:
Originally posted by TurboWood
I'm shooting for 300-350hp (turbo 4). From my calculations I'll be able to accelerate well over 1g in first gear which is almost surely more than the tires can handle. My biggest concern is just the driveability from a stop. I don't want to start a clutch burning business.
Paul,
Thanks for the feedback! That's the first b2b information I've found. I am more interested in the HD boxes in order to handle the power. As i'm in the US neither supplier is super convenient. There just aren't many options in the US for the type 9.
Daniel
quote:
Originally posted by Paul Turner
quote:
Originally posted by TurboWood
I'm shooting for 300-350hp (turbo 4). From my calculations I'll be able to accelerate well over 1g in first gear which is almost surely more than the tires can handle. My biggest concern is just the driveability from a stop. I don't want to start a clutch burning business.
Paul,
Thanks for the feedback! That's the first b2b information I've found. I am more interested in the HD boxes in order to handle the power. As i'm in the US neither supplier is super convenient. There just aren't many options in the US for the type 9.
Daniel
Only just spotted that you are taking about 300 -350 bhp. Forget the type 9, it simply will not cope with the power or torque. 260 bhp is normally quoted as the limit for a HD box and even then regular rebuilds are essential. A mate of mine with 250 bhp regularly breaks syncros, he uses steel ones on 1st and 2nd now but the box requires a strip to lap them in every 2000 miles or so.
You need a Borg Warner T5 box as used by Ford in the early 2WD Sierra Cosworth. Its bigger and heavier but since it originated in the Mustang it can cope with outrageous power and torque. The Sierra ratios are pretty OK but Quaiffe do closer ones in needed. TVR also used the box but the ratios are naff. Not sure what ratios the Mustang used.
But does anyone make a T5 bellhousing to suit your engine.
Paul,
You are right that the T5 would cover my power, but it won't fit in the chassis I have. It's unfortunate too because quad4rods actually does
have a bell housing.
I'm hoping the SPC or BGH will be ok since most of my driving will be on the street. So, it won't have to live with sustained 300+hp abuse.
On the track I'll probably need to dial it back a bit for cooling reasons anyway.
The quaife 56G is my backup plan, but I would hate to take out a mortgage for a transmission...
Daniel
All this talk about power is not really relevant, it is torque that kills gearboxes. I run a BGH E8 box in my Phoenix which has a Rotrex'ed
Zetec making 340BHP/260 ft lb on a 3.54 ATB English axle.
In this situation the box is marginal and I have linear power delivery unlike a turbo which while have a big lump of torque suddenly coming in. If
you go for the SPC or BGH you will likely be rebuilding it frequently. I am looking (at some stage) to change my Type 9 for either a 57G or 60G
Quaife which 'should' cope with the power.
+ 1
quote:
Originally posted by Paul Turner
Having had a Seven now for 25 years my personal opinion is the cars are all about rapid in gear acceleration for overtaking. A decent top for reasonable cruising is also required but in mine with a 3.9 diff it is doing 3500 rpm at 70 which is fine (although higher than many tintops).
If you fit a 3.14 diff with either a SPC or BGH box you will end up with a car that will theoretically do about 58 mph in first at 7000 rpm (depending on tyre size) and have a theoretical top speed of approx 175 mph. Such a high first gear will put quite a strain on the clutch. In a light car like a Seven its normally the tyres that break traction in the lower gears before the clutch slips unless the clutch is knackered.
Based on my personal experience I would not want a turbo in a Seven ever. Driven a supercharged car once, did not suit the character of the car. With 175 bhp and a weight of about 600kg my car will beat almost anything on the road and does not frighten me. It had 208 bhp at one time but on a normal road trip the car was no faster, it just used more fuel. I do not have to worry about the turbo coming on boost and throwing me off the road.
There are many Seven owners out there with 1.3 pushrods who have more fun than those with stupid power levels.
Just my opinion.
the T5 size compares quite well to a type 9 (smaller than a lot of other boxes folk have fitted in 7's) are you really so tight for space that
you couldn't make it fit
[Edited on 26/8/2013 by mcerd1]
quote:
Originally posted by jeffw
All this talk about power is not really relevant, it is torque that kills gearboxes.
BGH will tell you the torque rating of their various boxes, as will Elite. I've spoken to Quaife in the past and they have torque figures in
their site as well.
A 300HP Turbo car is much more likely to kill a box than a 300HP NA car or a Rotrex car. And this is simply because the torque comes in all at once
on most turbo cars.
So what are the realistic option for 350bhp and 270lbft of torque if wanting to something that will not break
Not a Type 9...56/57G Quaife or a T5.
this is what I did to a Type 9 with 260 ft lb
I'm running a BGH E8 alloy Type 9 with all the extra strengthening they can do and it is holding together at the moment. Brian and Chris are
talking about a stronger Type 9 but there is no timescale. If this one goes bang I'm off to get a 57G.
[Edited on 26/8/13 by jeffw]
How long did that take jeff?
About 5 Sprints. 3rd gear is very brittle if you use the standard Ford third (which the BGH E6 does). As I said the BGH E8 is in the car now and has
been for about 12 months but that is a Rotrex not a turbo...
[Edited on 27/8/13 by jeffw]
Jeff,
That is a good looking gear set . A little JB weld and it should be good to go.
Does anyone know of someone that has used the Quaife 56G transmission?
Daniel
Hi Daniel,
Sounds like it will be a ferocious little car when built.
I might have missed it above, but what engine are you planning to use?
quote:
Originally posted by jeffw
this is what I did to a Type 9 with 260 ft lb
I've always had the same BGH Type 9 in the car so when it went bang it seemed sensible to get it fixed (Alloy cased E8s have some value after all). A T5 is a possibility but I would be much more likely to so sequential for the next box (Elite IL300, Quaife 60G etc)
quote:
Originally posted by nick205
Hi Daniel,
Sounds like it will be a ferocious little car when built.
I might have missed it above, but what engine are you planning to use?
quote:
Originally posted by jeffw
....Alloy cased E8s have some value after all....
You guys make me thing I have to bit the bullet and get the quaife. I just wish I could find someone that has used it to offer some opinions.
Daniel
quote:
Originally posted by mcerd1
quote:
Originally posted by jeffw
....Alloy cased E8s have some value after all....
yeah, I've got a bargain iron cased E8 waiting to go into mine just now and I know how much that cost
the alloy case alone must have set you back a bit, do you know the total weight of your E8 ?
quote:might be worth having a look over on the westfield / caterham forums - I know quite a few of them use the quaife boxes
Originally posted by TurboWood
You guys make me thing I have to bit the bullet and get the quaife. I just wish I could find someone that has used it to offer some opinions.
It is quite common to use the dog box version (57G ?) in sprinting with the Westfield guys, those that don't use the 60G of course.