Lotus Elan

Strombergs or Webers

PostPost by: LarrySprint » Mon Dec 23, 2019 4:48 am

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.
LarrySprint
First Gear
First Gear
 
Posts: 15
Joined: 23 Mar 2019
Location: SoCal

PostPost by: tedtaylor » Mon Dec 23, 2019 2:12 pm

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.
TED
"Driving a Lotus is a triumph of bravery over intelligence." Stirling Moss
"TaylorMadeClassicCars" on WWW and Facebook
tedtaylor
Fourth Gear
Fourth Gear
 
Posts: 658
Joined: 09 Dec 2012
Location: Smyrna, Delaware, USA

PostPost by: Grizzly » Mon Dec 23, 2019 2:39 pm

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.
Chris
User avatar
Grizzly
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1964
Joined: 13 Jun 2010
Location: Cheshire/UK

PostPost by: nmauduit » Mon Dec 23, 2019 2:42 pm

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...
S4SE 36/8198
User avatar
nmauduit
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1476
Joined: 02 Sep 2013
Location: France

PostPost by: pharriso » Mon Dec 23, 2019 2:51 pm

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.
Phil Harrison
1972 Elan Sprint 0260K
User avatar
pharriso
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 2798
Joined: 15 Sep 2010
Location: Long Island NY, USA

PostPost by: steve lyle » Mon Dec 23, 2019 4:46 pm

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
1972 Elan Sprint 0248k @ https://www.mgexp.com/registry/1972-Lot ... 48K.30245/
1972 MGB Roadster @ https://www.mgexp.com/registry/1972-MG- ... 842G.4498/
2007 BMW 335i Coupe
User avatar
steve lyle
Second Gear
Second Gear
 
Posts: 162
Joined: 15 Jun 2015
Location: Tulsa, OK USA

PostPost by: pharriso » Mon Dec 23, 2019 8:30 pm

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...
Phil Harrison
1972 Elan Sprint 0260K
User avatar
pharriso
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 2798
Joined: 15 Sep 2010
Location: Long Island NY, USA

PostPost by: LarrySprint » Tue Dec 24, 2019 1:01 am

Thanks everyone for the input.
If my compression was 10.3:1, how much lower will it be using the early head.
LarrySprint
First Gear
First Gear
 
Posts: 15
Joined: 23 Mar 2019
Location: SoCal

PostPost by: rgh0 » Tue Dec 24, 2019 2:47 am

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
User avatar
rgh0
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 7511
Joined: 22 Sep 2003
Location: Melbourne, Australia

PostPost by: StressCraxx » Tue Dec 24, 2019 4:13 am

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.
There is no cure for Lotus, only treatment.
User avatar
StressCraxx
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1029
Joined: 26 Sep 2003
Location: San Francisco Bay Area, California

PostPost by: RogerFrench » Wed Dec 25, 2019 1:21 pm

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!
1967 Elan S3
1972 Europa Twin Cam
2005 Elise
User avatar
RogerFrench
Fourth Gear
Fourth Gear
 
Posts: 619
Joined: 01 Dec 2009
Location: Richmond, TX

PostPost by: The Veg » Wed Dec 25, 2019 2:04 pm

Emissions-stuff aside, I think the Strombergs itself is a bit unfairly maligned.
1969/70 Elan Plus 2 (not S) 50/2036
"It just wouldn't be a complete day if I didn't forget something!" -Me
User avatar
The Veg
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1516
Joined: 16 Nov 2015
Location: Atlanta 'burbs (southeast USA)

PostPost by: 69S4 » Wed Dec 25, 2019 4:52 pm

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.
Stuart Holding
Thame UK / Alpe D'Huez France
69 S4 FHC
Honda GoldWing 1800
Honda CBX1000
Kawasaki H1 500
Yamaha XS2
69S4
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1209
Joined: 23 Sep 2004
Location: nr Oxford UK

PostPost by: mbell » Wed Dec 25, 2019 5:26 pm

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.
'73 +2 130/5 RHD, now on the road and very slowly rolling though a "restoration"
mbell
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1667
Joined: 07 Jun 2013
Location: Austin, TX (UK Ex-pat)

PostPost by: My72Sprint » Thu Dec 26, 2019 5:47 am

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.
Tim Bartlett, Sprint 183K
User avatar
My72Sprint
First Gear
First Gear
 
Posts: 32
Joined: 17 Sep 2018
Location: Sacramento California
Next

Total Online:

Users browsing this forum: No registered users and 6 guests