16 replies to this topic

[Rufatiwe]

Hi all,

 

I have recently become an owner of the only Opel Speedster in the country. I really love how the car feels and handles, IMO this is next to no other car I have experienced and I say this as an owner Alfa 4C.

 

My only problem is lack of power with 2.2 N/A engine. I would like to address this by swapping GM V6.

 

I want to clarify that I am not considering turbo set up at all, as I really want a N/A responsiveness and feel. I thought about SC but I much prefer N/A. I also believe believe it would suite raw, analogue and responsive nature of this car much better than turbo or SC set up.

 

The reason I am considering GM V6 is because I think it would fit more easily as I found someone has fit turbo set up in an elise:

 

https://www.lotustal...the-fun.102052/

 

So far my main question is about engine and transmission.

 

There are a lot variants GM V6 engines and they change over generations. The new generations has exhaust manifold integrated into head which makes it light also easier to fit and route exhaust.

 

The transmission selection is also tricky. First of all ideally I need a transmission that will fit bolt on into existing mounts and would fit V6 bolt and also would fit the subframe with modification to the subframe. I am OK if I need to modify transaxle housing but not the subframe. The transmission also needs to be able to handle higher torque of V6. I have read f40 trans is reliable and handles good amount of torque, and fits the V6, however, not sure if it fits the subframe.

 

The final challenge with transmission is with gear ratios. A lot of swapped cars run awkwardly due to improper ratios. I know that for example f40 gearbox came with wide range of ratios, so there is some choice. However, I am not sure how to properly select it without testing. I am thinking of using exige transmissions as a go by as it has similar engine and weight.

 

Any help, feedback would be appreciated.

 

Thanks

Rufat

 

 

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Edited by Rufatiwe, 11 October 2024 - 11:40 AM.

[hairy]

Nice garage!

 

Mopeytitan tried fitting an A28NET http://www.vx220.org...nown/?p=1939202

 

Unfortunately most of the thread was lost due to the server failure but I don't think the project was ever finished.

[stevieturbo]

I would think it will be a lot of work, for very little real gain.

 

You will not find any transmission that bolts to original mounts, other than the original F23. You will need to make mounts for anything else.....surely in the grand scheme of things, that's easy ?

 

Perhaps a little more awkward, is ensuring you can select gears with whatever new transmission. A linkage can be a little more complex than simple mounts.

 

Pretty sure GM made some V6 models that used the F23 anyway ?

 

But using some common sense....the easiest V6 swap to do ( relatively speaking ) would just be a Toyota V6 and box from an Exige. At least that way, many parts will be available off the shelf, albeit it a price.

 

A n/a V6 will still be pretty tame, and add a weight penalty over a simply modified 4cyl.

[RC220]

Having not touched my engine (bar recent major service), I certainly can't provide advice.  But, I think you can get more out of the 2.2 - ITBs or supercharger - with less weight, and maybe cost than a V6 transplant.  That is where I will go next.

[stevieturbo]

Supercharger is of course the easiest, and does offer a modest improvement. Which does feel very nippy on the road. Ultimately unless a Harrop perhaps, they still lack power. But still retains instant throttle response.

So from that point of view is a no brainer.

 

The 4cyl Alloy GM engine, there are many variants and they do seem to be able to be a solid performer, without a huge weight penalty, which let's face it is what these cars are all about. Staying somewhat light.

 

I just can't see any n/a V6 being a huge performer, unless it's a fully built screamer.....or with a blower, which is what they did with the Exige too.

 

A lot depends on what it will be used for of course.

[hairy]

There are a number of SC owners running over 400bhp: http://www.vx220.org...running/page-22

[Ivor]

There are a number of SC owners running over 400bhp: http://www.vx220.org...running/page-22

I'd only be #7 on the turbo list

[Rufatiwe]

Nice garage!

Mopeytitan tried fitting an A28NET http://www.vx220.org...nown/?p=1939202

Unfortunately most of the thread was lost due to the server failure but I don't think the project was ever finished.

Thanks!

That is a lot of work! The opposite of what I wish) It was a great read though.

[Rufatiwe]

I would think it will be a lot of work, for very little real gain.

You will not find any transmission that bolts to original mounts, other than the original F23. You will need to make mounts for anything else.....surely in the grand scheme of things, that's easy ?

Perhaps a little more awkward, is ensuring you can select gears with whatever new transmission. A linkage can be a little more complex than simple mounts.

Pretty sure GM made some V6 models that used the F23 anyway ?

But using some common sense....the easiest V6 swap to do ( relatively speaking ) would just be a Toyota V6 and box from an Exige. At least that way, many parts will be available off the shelf, albeit it a price.

A n/a V6 will still be pretty tame, and add a weight penalty over a simply modified 4cyl.

My goal is not to achieve high hp numbers but retain the NA feel and feedback. GM 3.6 V6 in LGX form puts out 335 hp, that is already more thab twice the stock, so it is plently enough for me.

I think getting more than 200 hp from the stock na would be difficult and more than 250hp would be extremely difficult.

I can fabricate a mount for the different for example f40 transmission. I need to know if it would fit the engine bay without the subframe modifications. The elise example above had f40 trans and I assumed it does fit, however I am not sure.

I could not find any cars with f40 trans with 3.6 V6, most of them are 4 cyc or 2.6 v6.

[Rufatiwe]

Having not touched my engine (bar recent major service), I certainly can't provide advice. But, I think you can get more out of the 2.2 - ITBs or supercharger - with less weight, and maybe cost than a V6 transplant. That is where I will go next.

Id love the ITBs and even found a set for sale, however I am afraid I will never be able to get it tuned properly and achieve decent performance.

[Rufatiwe]

Supercharger is of course the easiest, and does offer a modest improvement. Which does feel very nippy on the road. Ultimately unless a Harrop perhaps, they still lack power. But still retains instant throttle response.
So from that point of view is a no brainer.

The 4cyl Alloy GM engine, there are many variants and they do seem to be able to be a solid performer, without a huge weight penalty, which let's face it is what these cars are all about. Staying somewhat light.

I just can't see any n/a V6 being a huge performer, unless it's a fully built screamer.....or with a blower, which is what they did with the Exige too.

A lot depends on what it will be used for of course.

SC is be my second priority if V6 doesnt work out. The LGX engine provides excellent performance and with transmission weightslightly more than z22se set up and i guess similar weight compared to turbo or sc set up

[OneYet]

Jaguar V6. All in swedish I´m afraid but theres a link to his Instagram there that might be in english. Or just Google translate it.

https://rejsa.nu/for...ic.php?t=120433

[hairy]

 

Nice garage!

Mopeytitan tried fitting an A28NET http://www.vx220.org...nown/?p=1939202

Unfortunately most of the thread was lost due to the server failure but I don't think the project was ever finished.

Thanks!

That is a lot of work! The opposite of what I wish) It was a great read though.

 

 

From what I remember he put it up for sale so maybe worth sending him a message to see if he has any parts you might be interested in.

[hairy]

Jaguar V6. All in swedish I´m afraid but theres a link to his Instagram there that might be in english. Or just Google translate it.

https://rejsa.nu/for...ic.php?t=120433

 

Wow! there is some serious engineering going on there.

[stevieturbo]

Jaguar V6. All in swedish I´m afraid but theres a link to his Instagram there that might be in english. Or just Google translate it.

https://rejsa.nu/for...ic.php?t=120433

 

I think that's along the lines of what the Caral roadster was ?

 

http://www.caral.co.uk/

[Mattias]

There is an option to supercharge and keep the feel of an N/A. Look at the option of fitting a centrifugal supercharger. Since boost increase with rpm it just feels like a bigger NA. Take my Jaguar V6 mentioned above as an example, it has the exact same power/torque curve as a BMW M5 V10, I run a Rotrex supercharger. 

You could probably get between 350-450hp peak and possibly on a stock engine since the low rpm torque is still not massive. 

 

Super responsive and linear feel to how it drives.

[stevieturbo]

There is an option to supercharge and keep the feel of an N/A. Look at the option of fitting a centrifugal supercharger. Since boost increase with rpm it just feels like a bigger NA. Take my Jaguar V6 mentioned above as an example, it has the exact same power/torque curve as a BMW M5 V10, I run a Rotrex supercharger. 

You could probably get between 350-450hp peak and possibly on a stock engine since the low rpm torque is still not massive. 

 

Super responsive and linear feel to how it drives.

 

Cool project, and lots of nice work there.