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When is enough bhp enough?

PostPosted: Tue Aug 15, 2017 7:44 pm
by poppy
Hello , I am new to this forum and have joined in the hope to learn from experienced owners. My five year plan to become a plus 2 owner is about a year away.. So now I am getting more focused on the right buying decisions to make. To me the plus 2 is not so much to a point, how fast you get there, but how you get there, wherever there is that is.. My experience is of original Lotus engine plus 2's and their bhp, nice but not trilling. But "Zetec" and now " Duratec" conversions seem to be more and more. One company offering " upto 280 bhp convesion !! Modern engine unit yes, can understand attraction in many ways but at what point is enough enough... If you cant use it whats the point having it. To me that is traction limit. What say you and thank you.

Re: When is enough bhp enough?

PostPosted: Wed Aug 16, 2017 8:52 am
by wotsisname
For me... I enjoy the Sweet handling of a Lotus. [My Comments are based on Road driving, driving an Elise & looking forward to driving my +2 again)
If you go too far with adding bhp then you may have to compromise this.. wider tyres, stiffer suspension, etc.

I road tested a 111R [190+BHP, track orientated suspension & tyres] back to back with an Elise S [140bhp]... I loved the "R" engine, fabulous sudden boost in performance... but the "S" set up was so much sweeter to drive.... I chose the 'S' and 10 years later still think I made the right decision.

Re: When is enough bhp enough?

PostPosted: Wed Aug 16, 2017 9:17 am
by XR40
Hi. For me, the enjoyment is the 'total retro package experience'. Each to their own, but I wouldn't get hung up on power (BHP) and speed but instead like to enjoy and respect an historic car and the experience of what it would have been like to drive it in the 60's/70's......classic car = classic experience. I agree with you that the +2's attraction is not how fast you get there but how you get there ie. acceleration, handling and the lovely sound of the twin cam.

Good luck finding the right car for you.

1968 +2

Re: When is enough bhp enough?

PostPosted: Wed Aug 16, 2017 4:16 pm
by prezoom
Having just completed the installation of a 2L Zetec in my previously non-engined Plus2, I can truthfully say it was one of my better decisions. My boy racer days are over, so the increase in engine power for the most part will only be used for occasional forays into the local mountains.

Installing the Zetec does take some fabrication, and purchase of some parts to make this happen. I went my own route, but basically followed the thread in the Mods Section on installing a Zetec in a Plus2. Far easier and cheaper in the UK, rather than here in the US. The only imported parts were the intake manifold and an exhaust manifold flange for my self fabricated exhaust system. The rest was obtained from ebay, Rock Auto and local sources. The flywheel/starter mods were a bit more than I had anticipated to get the Fidanza aluminum flywheel for the Zetec to work with the original (?) high torque pre-engaged starter. Anyone interested in what it took can PM me for a detailed explanation.

Going a little deeper on this, I chose to install Weber 152G carburetors rather than fuel injection for a couple of reasons, which related to overall cost. I had an Electromotive HPX crank fire lost spark advance adjustable electronic ignition. This system uses pots to adjust/retard/rev limiter, but does not manage the fuel system. Yestertech, yes, but it was an unused spare left over from my racing days. A bird in the hand, so to speak, and it worked then and it is working today. A Dunnell Engineering intake manifold to go with the carbs made sense to me because of the amount of Weber jetting I have collected over the years. Those carbs were a bit of a gamble, as Keith had pronounced the 5 progression holes as unworkable. However, it seems just recently his may be changing his mind. My initial jetting was a bit of a SWAG, even with some suggestions from the commentators on One repeated suggestion for idle jetting was a 60f6, a .70 air bleed, which is very rich, probably causing dimished fuel mileage. So, I started with 55F8, .120 air bleed. Less fuel and a whole lot more air. With that initial jetting, the car has absolutely no hesitation/bog/gasp, and the acceleration at small throttle depressions is amazing. More work to be done as I continue to drive the car.

One thing that raised its ugly head is the need for a 3.54/5 speed/close ratio transmission. The 3.54 is being installed as I speak. I also have a type 9 and appropriate bell housing, but am reluctant to go through the process of the shift lever conversion, as the gear ratios are not what I think the car needs. On the garage floor is a close ration 2000E that was destined to replace the middle close that was installed in my S2 when I purchased the car. But the Plus2 would be a delight to drive with the added torque and the close ratio gears. Decisions, decisions.

Re: When is enough bhp enough?

PostPosted: Wed Aug 16, 2017 6:55 pm
by dunclentdr1
Depends what you want! I am lucky enough to have some Elans which range between 120 and 150 bhp - but also a 210 bhp 1969 Europa - fuel injection, starts every time and a little more power than you might want in a car originally having 75bhp - would I recommend lots of power in an older car - yes and it really makes you work at driving style, slower in but very fast out!


Re: When is enough bhp enough?

PostPosted: Thu Aug 17, 2017 12:57 am
by stugilmour
I think the Plus 2 sweet spot is probably around the 170 to 180 hp that the Zetec or Tall Block Twin cam offers. The 3.54 diff and MT75 five speed (or whatever you have to hand with approx. 0.82 fifth) provides 80 mph cruising at 3500 rpm, which is perfect GT performance and really settles down the noise level. ~30% more power to take up the roughly 20% weight penalty and the tall gearing seems about right.

I have tracked my Plus 2 (with five speed & tall diff, stock Stromberg TC, stock suspension & tire configuration). It desperately needed more power, but not a ton. There is a heck of a lot of body flex and rear jacking at track speeds; completely stable & enjoyable but probably not suited to a bunch more power.

I am presently installing a Tall Block, and hopeful it will be just fine. :D If I were going from scratch or in the UK close to all of your specialists I would have probably gone Zetec, but the required frame mods were beyond my ability/desire.



Re: When is enough bhp enough?

PostPosted: Thu Aug 17, 2017 8:36 am
by theelanman
I prefer corners to straight lines....the 140bhp that mine is chucking out is more than capable of throwing the car round the corners faster than most modern stuff as it is........and plenty enough umph to shoot past stuff if I wish.....

Ive seen an elan (2 seater) with a 2ltr vauxhall red top engine from a BTCC car in it that was tuned to about 250bhp.........whilst it was blisteringly fast in a straight line is was virtually impossible to get any of the power down in the corners on a wet day

I suppose the other thing being what are you plans for the car?.....
tracks/racing......or just general classic motoring.......if it was the latter Id stick with stock.....if the former probably Cosworth Duratec.........(hey why not....if youre going to do may as well go the whole hog.... :mrgreen: )

Re: When is enough bhp enough?

PostPosted: Thu Aug 17, 2017 10:25 am
by jimj
If you want a great classic car, buy a Lotus. If you want a hot rod buy a hot rod.

Re: When is enough bhp enough?

PostPosted: Thu Aug 17, 2017 11:32 am
by Certified Lotus
I've got 150 HP in my S1. Its plenty of power and wouldn't want more (I can't believe I just said that but it's true).

Re: When is enough bhp enough?

PostPosted: Thu Aug 17, 2017 3:35 pm
by prezoom
Any time when you get less than 10 pounds per horse power, you will be getting serious performance. An Elan with 175 hp, even with a 180 lb driver is approaching that number.

Re: When is enough bhp enough?

PostPosted: Thu Aug 17, 2017 4:13 pm
by Quart Meg Miles
Welcome, Poppy!

Test drive a +2 S130 and use that as your yardstick. A 130/5 has good touring gearing and the handling is superb and safe in standard form.

Don't spoil a standard car by modifying it drastically, there are plenty which are already tweaked beyond recovery IMHO.

Re: When is enough bhp enough?

PostPosted: Thu Aug 17, 2017 5:23 pm
by CBUEB1771
The conversation should always start with your planned use for the +2. I presume that ultimate performance is not the goal, otherwise the 30+% weight penalty of a +2 compared to an Elan would be a fatal flaw. I also think that torque is the more relevant parameter for the engine. A Twin Cam with a 1600-stroke crankshaft benefits the +2 nicely and is an invisible modification. If the benefits of a modern engine are paramount a better choice might be an Elise.

Re: When is enough bhp enough?

PostPosted: Thu Aug 17, 2017 5:50 pm
by mbell
You should also consider how you want to drive the car, as they say sometimes it more fun to drive a slow car fast than a fast car slow.

So if you want a car thou can drive hard you don't want to increase the power much, a standard big valve car is ~8 seconds to 60 so not slow as standard. If you add lot of power it will be too fast to use on the road if pushing it hard. If you don't want to push it hard and more cruise around you could increase the power and torque a bit more.

One of the attractions of the +2 for me was us a car you can drive hard on the road with out going silly speeds. Which is not the case with my daily car which at times is frustrating as you can't plant your foot and run it out almost all the time but the mid range makes it a great daily car to drive.

I run 5 speed and 3.54 diff so do feel like some extra power would be good but probably 140/150 ish.

Re: When is enough bhp enough?

PostPosted: Fri Aug 18, 2017 2:10 am
by prezoom
It isn't so much the horse power that I enjoy, it's the torque. My S2 is a standard 105 hp with a 3.9. Climbing out of my driveway with the Plus2 was an eye opener for me. The increased torque was immediately noticeable with the Zetec. I have a tall block Weber engine sitting on an engine stand that needs a complete overhaul. When complete, I had planned on putting in the Elan. As the saying goes: "There ain't no substitute for cubic inches".......... unless you add a turbo.

Re: When is enough bhp enough?

PostPosted: Fri Aug 18, 2017 5:17 pm
by Spyder fan
On the road in the real world 180 + BHP is very nice, but it's useless unless you have 140+ lb torque at below 2500 rpm to go with it. To do that, you need a Zetec, Duratec or tall block twincam displacing at least 1750cc, preferably with throttle bodies and programmable ECU.

I very rarely use all the BHP, but the torque which gives the driveabilty is there from quite low revs.