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light and torquey RWD engine and automatic transmission
Littlejohn7895 - 3/3/18 at 12:51 PM

Hi everyone,

I am building a custom chassis which I am to install either a 4 cylinder or V6 of between 2.0 and 2.5 litre capacity, but this time the set up requires that I use an automatic transmission and not a manual.

My wish list for an engine and trans combo is:

1. Relatively light weight (so no big V6s or iron lumps);

2. Torquey motor in preference to high revving;

3. Not wanting to adapt a FWD engine as I do not have time or money to mess around trying to fit other transmissions and then modify the electronics to suit, or worse still, incurr the time and expense of an aftermarket ECU; and

4. Be from a donor car which can be bought for less than £1,500.

In order of preference, the donor options that I have so far narrowed it down to are:

1. Vauxhall Omega 2.2 litre with 4 speed auto; or

2. Mazda MX5 2.0 litre with 4 speed auto; or

3. Jaguar S Type 2.5 litre V6 with 5 speed auto.

The Jag is likely to be the heaviest and the MX is likely to be more revvy so the Omega seems to be the front runner but I wondered whether anyone had used any of the above combinations or could advise whether any present any particular difficulties I should consider before buying?

Thanks in advance,
Matt

morcus - 3/3/18 at 02:28 PM

of your options the Mazda would be the best one to go for. I believe the first MX5 auto also shares its gearbox with a small van.

For the Omega you are probably better off with the V6. I could be wrong but I believe the 2.2 isn't the same engine they put in the Vectra and Astra (which was a good engine) but a much more agricultural unit. It might even be heavier than the V6 (From vague memories of things I read in Performance Vauxhall magazine 5-10 years ago).

For convenience I would take a look at the 3 series as your budget would give you a wide range of possibilities and options as you'd have about 20 years worth of models to choose from and they offered autos on pretty much every engine.

B33fy - 3/3/18 at 07:14 PM

If you opt for the Jaguar running gear, check the rear diff requirements, the manual needs at least a 3.14 Sierra diff to keep the revs down.

SPYDER - 3/3/18 at 08:11 PM

The Omega will be an iron block.

ian locostzx9rc2 - 3/3/18 at 08:41 PM

Mazda or as some said bmw maybe worth a look

dinosaurjuice - 5/3/18 at 08:34 AM

Theres quite a few early Mercedes C180 kompressors kicking about for not much money. I've not done ANY research but i presume they're RWD, more than likely auto, and supercharger means good torque and easily tuned? Might be worth a look

Will

40inches - 5/3/18 at 09:15 AM

quote:
Originally posted by B33fy
If you opt for the Jaguar running gear, check the rear diff requirements, the manual needs at least a 3.14 Sierra diff to keep the revs down.


I started with a 3.6 and it was sprightly to say the least, now on a 3.3 and while it is better cruising at 70ish I miss the sparkle.
With hindsight I think I would leave the 3.6 on.
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[Edited on 5-3-18 by 40inches]

ss1turbo - 6/3/18 at 09:18 AM

quote:
Originally posted by B33fy
If you opt for the Jaguar running gear, check the rear diff requirements, the manual needs at least a 3.14 Sierra diff to keep the revs down.

I have a feeling that this is the case with the manuals as their 5th gear is a 1:1; not sure if it is still the case with the Auto though?

Any size constraints? The Omega V6 is quite a compact unit as it's only a 54 degree V6 which really helps when you've got the DOHC heads on (it's about the same as a pushrod V6). It's not that heavy either - probably much more than a 2.0 iron block engine. Jag unit isn't exactly tiny either, especially when you try and keep the inlet pipework (which I think it needs to produce the low down torque).

There are 2 GM 2.2 engines (one chain driven, one belt driven), and the Omega has the less desirable of them. To lug around that shell though, it is reasonably torquey but will need a lot of the Omega electrics to be able to run (including the clocks IIRC) whereas the earlier 2.0 is easier to run standalone - just needs the immobiliser circuit (ECU, receiver and key chip) hiding somewhere.

Merc V6s (M112?) are 90 degree units - so hellishly wide. 4-pots tend to use the same amount of underbonnet space as well.

40inches - 6/3/18 at 10:17 AM

quote:
Originally posted by ss1turbo
quote:
Originally posted by B33fy
If you opt for the Jaguar running gear, check the rear diff requirements, the manual needs at least a 3.14 Sierra diff to keep the revs down.

I have a feeling that this is the case with the manuals as their 5th gear is a 1:1; not sure if it is still the case with the Auto though?


The manual is 1:1 with a 3.07 or 3.14 diff, the Auto is 0.75:1 with a 3.31 diff
With the 3.3 the MK is geared for 145mph. The Auto is vastly over geared on the S Type with the same diff ratio 180+MPH
So a 3.6 or 3.3 would work well
A lot of info here http://www.automobile-catalog.com/make/jaguar/s-type_2/s-type_2_1/2001.html

[Edited on 6-3-18 by 40inches]

[Edited on 6-3-18 by 40inches]

Littlejohn7895 - 6/3/18 at 04:34 PM

Thank you very much all for your great responses.

Based on these I will refine my choice to:

(i) 1.8 or 2.0 MX5,

(ii) Vauxhall 2.0 - SS1turbo, did you mean to say that there are two GM 2.2 litre engines of which the Omega one is the less preferred. Or did you mean to say that there is a 2.0 and a 2.2 and the 2.0 is the better option? If there is a second 2.2 engine, what is it from?

(iii) Vauxhall 2.6 V6 if it is not too much heavier or longer than the 2.0.

The Jag sounds like it will be too bulky.

The Mercs are an interesting prospect - especially with the kompressor and the BMWs are an option too. Cheap and easy to work on donors appear to be an early MX5 though.

I should have mentioned that top end speed is not important, it is unlikely to exceed motor way speeds.

Thanks everyone

alistairolsen - 6/3/18 at 06:31 PM

quote:
Originally posted by Littlejohn7895
Thank you very much all for your great responses.

Based on these I will refine my choice to:

(i) 1.8 or 2.0 MX5,

(ii) Vauxhall 2.0 - SS1turbo, did you mean to say that there are two GM 2.2 litre engines of which the Omega one is the less preferred. Or did you mean to say that there is a 2.0 and a 2.2 and the 2.0 is the better option? If there is a second 2.2 engine, what is it from?

(iii) Vauxhall 2.6 V6 if it is not too much heavier or longer than the 2.0.

The Jag sounds like it will be too bulky.

The Mercs are an interesting prospect - especially with the kompressor and the BMWs are an option too. Cheap and easy to work on donors appear to be an early MX5 though.

I should have mentioned that top end speed is not important, it is unlikely to exceed motor way speeds.

Thanks everyone


Im raking into my 10 year old memory as a vauxhall enthusiast, but there was the X22XE which was an iron blocked version of the X20XEV ecotec engine but taller, it came in fronteras and omegas and stuff. THen there was the Z22SE which was the all alloy engine in the astra/vectra/VX220 which was an altogether different beast.

The vauxhall V6 is the same basic engine as the 4 pots, with a common block, so the rods/pistons/heads are 50% more, the cam pullies and bits are double and the crank and block are not quite double. It's not a light engine.

At the end of the day it depends what you want. Do you need lots actual torque in ftlbs if you're not exceeding motorway speeds, or just the nature of an engine which makes peak power well down the rev range? How much power do you actually need? You're looking at engines making 120-170bhp ish?

You say you dont want to convert a transverse engine, but what conversion is required? Volvo T4 is all alloy and in that power bracket for example. You want a light engine, but how light is light? a vauxhall V6 certainly isnt.

Littlejohn7895 - 7/3/18 at 12:31 PM

Thanks again. A factor in all of this is the rear end which has a ratio of 4.27:1. I believe that the early 1.6 and 1.8 MX-5s had very similar ratios but that a 2.0 or 2.2 Vauxhall could give a little more punch low down given that an auto is usually a little more sluggish than manuals. But the characteristics of the Mazda engine and trans seem to make it an attractive option.

I now recall having initially looked at the Z22SE but unless I am mistaken, I think it is only used in FWD applications and I am trying to keep costs and difficulty down by seeking a RWD with automatic that I can completely remove with all ancillaries and electronics. I could not find any details of anyone having converted a Z22SE to RWD automatic. In any event I suspect it will require machining parts and a custom ECU to run the engine and trans which I would prefer to steer away from for both cost, time and difficulty factors.

I'll ditch the V6 from consideration altogether though.

Cheers, Matt

ss1turbo - 12/3/18 at 02:20 PM

The weight of the Vauxhall V6 is relative, I guess - I swapped a Ford Essex out and put one of them in its place but the Essex is jokingly heavy enough to generate its own gravity..

I think by the time the Z22SE came in, there weren't any RWD petrol Vauxhalls left to put it into - not "new" ones anyway.

I thought the MX-5 had a 3.9-ish diff ratio? If you're after something which can cruise at a relaxed RPM, then a 4.27 rear axle isn't the right way to go unless you're fitting very large rear wheels or find something with a 0.6 top gear.. If, however, you''re making it for trials, then that's a completely different set of criteria.