Future kit builder

[Paul904]

Hello there,

Quite a few years ago I purchased a home built Hawk HF3000, which for financial reasons I sold a few years later. My plan is to build a Lister Bell STR, which realistically I won't be able to start for 18-24 months or so. I was thinking of buying a 2.5 156 as the donor, because it's a nice revving engine, plus they're cheaper to buy. Eventually I would like to have different cam shafts fitted, and also independent throttle bodies too. However the bloke who works on my Alfa 75 V6 reckons the 2.5 doesn't have much torque, and the 3.0 is much better. Any thoughts please?

regards

paul

[turbonutter]

You mention the 2.5V6 as the donor is cheap - which is true, but then you want to add cams & ITB's, which will also need an ECU & possibly pistons, which I would budget at least 4K for? If you want an Alfa engine, then get the 3.2V6, which will give you more power/torque than the tuned 2.5V6 and although the engine is not cheap, you can get them for under 2K.

[Normb666]

Hi Paul, and welcome to the club!

I've bought a 156 V6 as a donor for a Lister Bell too - I umm-ed and ahh-ed over the 2.5 vs. 3.0 (and 3.2) choice for a bit, and decided that, OK, maybe the 3.0 has more torque, but it's not like there's that much weight to be dragged around in the finished car...and having driven the donor around for a few months to make sure all's good, I can't honestly say it's lacking in performance for what it is! Sure, it's definitely "top-endy", but the noise it makes is fabulous, so that's not much of a hardship to endure!
My plan was to build the car using the 2.5 pretty much straight from the car, just tarted up a bit, and put it on the road using the donor car's V5 to get an age-related plate. Then, after a year or so, get hold of a 3.0 or 3.2, spend some money on that (cams, ITBs, new ECU, whatever) and swap over the manifolds and single-mass flywheel from the 2.5. I even thought about keeping the 2.5 box and installing a Quaife diff - the lower final drive should make for really good acceleration. Actually, if you're not modding the motor, you can even just swap the 2.5 for a 3.0 and use the 2.5 ECU so long as you use the 2.5 injectors, or that's what some guys on the Alfa forums have done (the lambda and MAF tell the ECU the engine's breathing really deeply, but the software's good enough to cope, apparently).

Whatever, the thing I'm trying to say is, if you go for a 2.5, you've not hit some kind of dead end. You can concentrate on getting the rest of the car right while running with a perfectly acceptable standard motor that does all the cold-starting stuff etc. that regular production cars do, and if you find down the line that you fancy a bit more go, it's no big deal to upgrade and you've already got the correct flywheel and nice manifolds. But it's a very personal thing - some people jump in with both feet and go for the full modded powerplant right from the off. All down to how much dosh you've got and how much grief you want to give yourself - just remember, it's supposed to be fun!!

Let us know which way you decide to go!

Cheers

Norm

[Paul904]

I’ve decided to put a deposit down on a turnkey LB STR, 3 year waiting list but it gives me time to save. Still not sure about which engine to go for though!

regards

Paul

[Normb666]

Congrats on finally making the decision, Paul - but now you'll have to change the thread title

As it happens, I decided to forget the Alfa base after a change in circumstances last year, and now I'm going Toyota (already got the motor and box). I think the Busso motor's great - smooth, sounds fab, etc. etc., but in the last 12 months I've noticed the donors seem to be getting thin on the ground or expensive (compared to what they were)...plus they're not cheap to tweak! Might be an idea to start donor-hunting now, and stash it away till you need it!

[Bernard]

I suspect that a well built 2.5 with cams, TB's, exhaust.. etc will have more than enough power.... so would you need the torque of a 3.0 to shove a 950kg car round ? (as Normy say's)

Up to you though... we all have the freedom of choice !

Phil