Holden V8 vs Opel 3 liter

[028 Sean]

You can also use the LSD (3.70) from a Senator B 24V if you change a few things but its a cheap way to make a LSD because all 24V Sennies have a LSD.

Oh no....here in the UK they DIDN'T!!!



The only Senator B's that had LSD's fitted as standard equipment were the ones used by our Police forces as Patrol Cars. Unless the private buyer who bought his Senator B new from his local Vauxhall Dealer specified the fitment of an LSD and paid extra for it, the Senator B left the Opel factory in Germany with either an 3.45 : 1 (earlier model) or 3.70 : 1 (later model) open Differential. All Carlton GSi 3000 24v's (same as Omega 3000 24v) after 1990 had an LSD fitted as standard at no extra cost though Ben!



And the only other Vauxhall/Opel vehicle that had the standard fitment of a (3.45 : 1 Holden derived unit) LSD was the Lotus Carlton/Lotus Omega!



As for swapping Differential ratios....you can make up a 3.90 : 1 unit for an Omega A 3000/Senator B by using the crownwheel & pinion from an Omega B's rear Differential. This will give you slightly quicker acceleration but on the downside you'll loose about 5mph top speed.

HTH!

[014 Phil]

How good does that Lotus Carlton look?? Never knew it ran a Holden diff centre! You learn something new every day.

Thanks for the info Ben. I will be using local Commodore brake components which will be easy to source.

Not sure what I'll do about the diff centre, but will worry about that when it's getting closer to completion. 3.15 does sound like a good ratio. Anyone know what diff ratio I would currently have in the Royale?

[118 Ben N]

G,day Phil the current ratio is very easy to check,just take the cover off the diff and look at the numbers on the biggest gear wheel i gues it would be 11:38 and than you have to do this:38:11=3.45.
You cant see it from the outside of the diff,also to see if they have LSD you have to take the cover off or lift the car completely and turn the wheel on one side if if both wheels turn the same way you have a LSD if one wheel turns the opposide way and you turn you have a normal diff.

Opel did this (1978-1982):
3.45 is used always in the A1 (as far as i know) behind al engines and tranny,s

In the A2 (1983-1986) they did this:
All 4 cylinders had a 3.7 ratio (and i believe the 2500 in combination with a 4-speed automatic because the lack of torque)
30E with 5 speed manual and 4- speed automatic had a 3.45
30E in combination with the 3-speed automatic only used the 3.15.(but the 3-speed auto was only availeble in the year 1983,in 1984 the Aisin Warner 4-speed gearbox with lockup in introduced.

[118 Ben N]

Yeah Sean that right the older models with 12V engines had a 3.45 and the later 24V engines in both Omega A and Senator B had a LSD but a ratio of 3.7.

We put a 3.7 diff from a 4 cylinder A2 Monza in my brothers Monza in combination with a Getrag 265 gearbox and 24V engine it now has a top speed of 240 km an hour measured with GPS on the Germay highways where there are no speedlimits (i live 10 minutes from the German border).
Before with the 3.45 it was a bit slower in acceleration but for better acceleration and a higher topspeed we build in a 3.7 diff because the engine dint had enough power to get it to 240km/h before the diff swap.

If somebody is interested in doing a 24V conversion in a Monza/Senator A,i know an adres where you could get custom build flywheels that fit the 24V engine and where you can screw you old 30E clutch back on and use a 240 or 265 Getrag transmission,and on those flywheels you can also use a changed BMW 635CSI clutch that can handle up to 500NM (for 4 liters of 3.0 24V that use a turbo or whatever).

[028 Sean]

Never knew it ran a Holden diff centre! You learn something new every day.

They sure did! According to the Ian Adcock book about the Lotus Carlton/Omega, they had to use a Holden 3.45 : 1 Differential because it was the only thing that would fit from the GM parts bin that was strong enough to handle the Lotus's 3.6Litre 24v Twin Turbo engines huge amount of Torque!

[020 Brad]

If somebody is interested in doing a 24V conversion in a Monza/Senator A,i know an adres where you could get custom build flywheels that fit the 24V engine and where you can screw you old 30E clutch back on and use a 240 or 265 Getrag transmission,and on those flywheels you can also use a changed BMW 635CSI clutch that can handle up to 500NM (for 4 liters of 3.0 24V that use a turbo or whatever).

I'm interested in that! I have a 24v Omega A and the manual gear from a 12v Omega, as the 24v manual stuff is very very difficult to find here from what I have seen.

I was just going to make something up here for around NZ$400 to my own specs but if I can buy a custom built jobby that would do the job then thats surely the easiest option.

[118 Ben N]

Those flywheels have 8 holes to fit the 24V crankshaft.

All other crankshafts have 6 holes:20E 22E 25E 26i 2800E 30S 30E 3.6i

With such a flywheel you can keep your own transmission in the car (Manta/Rekord/Senator A/Monza A) if you do a conversion to a 24V,and you dont have to use the standard 24V transmission and use that heavy flywheel and change the tailshaft an all that...

Here you can see some pics of such a flywheel and a normal 265 Getrag Monza transmission together (and it works i know,because its my brothers car)

[118 Ben N]

Here the link that i fogot :

http://www.bigopels.nl/forum/viewtopic.php?f=11&t=4591

[028 Sean]

I'm interested in that! I have a 24v Omega A and the manual gear from a 12v Omega, as the 24v manual stuff is very very difficult to find here from what I have seen.

Hold your horses Brad!

The Opel Manta 240 Getrag gearbox and the stronger Opel Monza 265 Getrag gearbox are totally different to the R25 Getrag gearbox that was fitted to the earlier 12v Omega 3000 and also the later R25/R28 Getrag gearbox for the Omega 3000 24v Brad!

These Manta/Monza items are not directly interchangeable with Omega A items at all without lots of mods like the re-location of the transmission mounts, re-engineering the propshaft to suit the ealier Monza gearbox, different clutch cable if its a R25 or re-engineering away the hydraulic clutch system on the 24v if its an R25/R28 gearbox, etc, etc....

The gears on these gearboxes are in different places too mate!

Manta 240/Monza 265 Getrag gear spacings are :-

R - 1st - 3rd - 5th
- 2nd - 4th

Reverse gear is on the far left passed 1st gear on the Manta/Monza gearbox where as the Reverse gear is inline with 5th gear on the later Omega A R25 & R25/R28....

Omega 3000 R25 & R25/R28 Getrag gear spacings are :-

1st - 3rd - 5th
2nd - 4th - R

That above is a kinda crude way to try too explain this on a computer Brad but I hope you understand what I'm getting at mate!

HTH!

[118 Ben N]

Yeah what Sean writes is completely true,those flywheels are only good if you plan a 24V conversion into a Monza/Senator or whatever car with a Getrag 240/265 transmission.

So that you dont have to change everything for the R-serie gearbox like hydralic clutch and tailshaft and more of those nasty things,and if you plan to do a powerfull 24V conversion like the 4 liter 24V with 200KW you can use a strong clutch on those flywheels too,so if you have a powerfull 24V and a strong clutch and a Getrag 265 you have a solide combination that can handle all the power.

You can also use that flywheel on a R-serie transmission in combination with a normal 30E (or stronger clutch) but you need the friction plate of a Getrag 265 with (that has the same amount of splines as R-serie friction plate) and springs,because the R-series transmissions have no springs in the friction plate because the task of the springs is taken over by the heavy 2 mass flywheel (16kilo) and that flywheel i am talking about weights around 9 kilo,and with a changed BMW pressure plate it can handle up to 500NM.

So you dont really need one Brad if you use all Omega/Senator B parts.

[020 Brad]

Ok, all good information I'm sure but I still needa flywheel that will bolt to a 24v, so will the above mentioned flywheel not work?

[118 Ben N]

Yeah it shut work with a R-Serie transmission and a 30E clutch,the engine wil even fatser go high in the rpms because the flywheel is almost 50% lighter.

But to be 100% i am right i,ll check it if it work,ill contact a guy that has that flywheel in combination with a 24V and a R-serie transmission so that i know exact what parts he used.

[021 Chad]

Hey Brad, if it's just a matter of hole numbers and locations, surely you could drop a spare flywheel into the local engineering shop for a bit of PCD drilling?

[020 Brad]

Hey Brad, if it's just a matter of hole numbers and locations, surely you could drop a spare flywheel into the local engineering shop for a bit of PCD drilling?

Do people do that? Thats fucken crazy to be honest with you.

I need to change from 6 bolt to 8 bolt, but aside from that, drilling a multi-stud pattern into any flywheel is just asking for trouble. Imagine this with 12 holes in it!


I will just get one made, like I say, as I have a flex plate with the correct pcd and a flywheel with the correct sizing and offset, but if I can get one that people use all day every day and have done for years I would much prefer that just for ease of use more than anything. It would need to price up well though to be honest because I can get a billet flywheel made for around the $400 mark I think.

[021 Chad]

LOL yuh,
You'd have to get a blank flywheel machined up and new holes drilled. With 6 existing holes you'd need to weld them up and re-drill, then you'd have a grenade under the bonnet! boom!