Lotus Elan and Lotus Elan Plus 2 Forums

Would converting to weber carbs hurt the value of my Sprint or add to the value or just be a wash ?
The head I would use is an early half moon head. It does have big valves.
Thanks for your input.

generally it adds value, especially to the resto-mod crowd. The purists might snicker who want originality. speaking of value, you'll be spending a lot more investing into the conversion and may not get that investment back out of it. as with any restoration, you do it because you want it or love it that way.

IMHO skip the webers and go straight to Fuel injection....... if you are not bothered about originality Fuel Injection just works way better in almost every respect.

LarrySprint wrote:Would converting to weber carbs hurt the value of my Sprint or add to the value or just be a wash ?
The head I would use is an early half moon head. It does have big valves.
Thanks for your input.

I'm not sure how well the early head would fit the picture, not only because it would not match the period of the Sprint, but also because even with big valves they would flow less than proper Sprint heads...

If the rationale is to gain performance, I would precisely factor in all costs vs. the target performance figure (and the required amount of porting to achieve that), also considering a rebuildable used head of the later style or even a new head. It is very possible you'd end up with less performance with the stock old weber head even fitted with big valves vs. the original Stromberg if all is in good nick...

LarrySprint wrote:Would converting to weber carbs hurt the value of my Sprint or add to the value or just be a wash ?
The head I would use is an early half moon head. It does have big valves.
Thanks for your input.

I have precisely that & I think it's about awash.

Originality nuts prefer the car as it left the facxtory, but as discussed in another thread at the moment the Federal emissions stuff took 16hp away.

pharriso wrote:

LarrySprint wrote:Would converting to weber carbs hurt the value of my Sprint or add to the value or just be a wash ?
The head I would use is an early half moon head. It does have big valves.
Thanks for your input.

I have precisely that & I think it's about awash.

Originality nuts prefer the car as it left the facxtory, but as discussed in another thread at the moment the Federal emissions stuff took 16hp away.

But if you swap headers for the cast iron manifold, remove the crosssover pipes & secondary throttle plates, recurve the distributor and change the carb needles, can't you get that 16 hp back for much less expense/trouble than going to webers? (I hope so, because that's what I did - and if "feels" like I got a good chunk of those ponies back).

steve lyle wrote:But if you swap headers for the cast iron manifold, remove the crosssover pipes & secondary throttle plates, recurve the distributor and change the carb needles, can't you get that 16 hp back for much less expense/trouble than going to webers? (I hope so, because that's what I did - and if "feels" like I got a good chunk of those ponies back).

You?d be missing the higher compression (due to the head), but I think you?d be close...

Thanks everyone for the input.
If my compression was 10.3:1, how much lower will it be using the early head.

LarrySprint wrote:Thanks everyone for the input.
If my compression was 10.3:1, how much lower will it be using the early head.

The 4.60 inch thick high compression sprint heads had a nominal 10.3:1 comp ratio. The 4.64 inch thick earlier heads had a nominal 9.8:1 comp ratio. However most heads have been skimmed and otherwise changed over the years ( e.g. larger valves and changed combustion chamber shapes) and also blocks skimmed and pistons changed so you really need to measure and check as you cant rely on the standard numbers unless everything is to original dimensions and unmodified.

cheers
Rohan

The webers look cool and have a nice roar at WFO. Depending on the cams, cam timing, etc. they can be a challenge to get jetting and emulsion tubes right for drive-ability. Keith Frank's kits of bits are a huge improvement.

On the other hand, consider some tuning with the Strombergs. I have driven several well tuned twincams on Strombergs that were more than the equal of a twink with webers.

YMMV.

Anyone who thinks that a Federal Twin Cam with all its attendant gubbins is only 16bhp down on an uninhibited UK spec Sprint engine is dreaming.
However, Lotus themselves got Stromberg-carbed engines to produce decent 115bhp-ish output without going nuts and my own Europa TC with D-type cams, header, new distributor, high-level intake adapters and all gubbins gone goes a lot better than it did, so good luck to you!

Emissions-stuff aside, I think the Strombergs itself is a bit unfairly maligned.

The Veg wrote:Emissions-stuff aside, I think the Strombergs itself is a bit unfairly maligned.

Do we have any idea how much the Webers (or DellOrtos) are worth over a same spec tc on Strombergs?
On the face of it they look like simple things compared to the twidlers paradise that are Webers but the subtlety in the design is often overlooked.

I am no expert but I'd expect the two to be closely matched until you got in to higher bhp engines.

The Weber's can flow more air and probably more fuel so better for high bhp engines. Strombergs are probably easily to tune thou, do more likely to more optimally tuned that Weber's.

I have a new TwinCam Webers equipped with MSD Distributor + MSD 6AL. Plenty of power.

Depending on Webers perform, startup drive-ability etc. I may further update to injection, DTAFast S40 Pro ECU and w/Jenevy classic 45mm DCOE throttle bodies, looks like webers but it's injected.

I still have the original number matching Stromberg BV TwinCam but 113hp just didn't wasn't enough, just wanted to keep it original just in case.