Lotus Elan

webber carb conversion stromberg head

PostPost by: [email protected] » Thu Jun 12, 2008 6:54 pm

hi all tried to upload pic but camera has to many pixels , so have found club lotus member that took pics on sunday at knockhill,
email ,. joe [email protected] , joe will gladly email pics , that should sort that , cheers del
800bhp escort cosworth, 1000bhp nissan skyline , rs200, ,rs 500 ,lotus europa twin cam ,lotus elan s4 rolling road , ecu remaps, powder coating ,like making things that work, do all my own engine work ,worked for cosworth,lotus , porsche, aston martin
[email protected]
First Gear
First Gear
 
Posts: 24
Joined: 09 Jun 2008
Location: lanark

PostPost by: [email protected] » Thu Jun 12, 2008 6:55 pm

hi all tried to upload pic but camera has to many pixels , so have found club lotus member that took pics on sunday at knockhill,
email ,. [email protected] , joe will gladly email pics , that should sort that , cheers del
800bhp escort cosworth, 1000bhp nissan skyline , rs200, ,rs 500 ,lotus europa twin cam ,lotus elan s4 rolling road , ecu remaps, powder coating ,like making things that work, do all my own engine work ,worked for cosworth,lotus , porsche, aston martin
[email protected]
First Gear
First Gear
 
Posts: 24
Joined: 09 Jun 2008
Location: lanark

PostPost by: CBUEB1771 » Thu Jun 12, 2008 8:32 pm

[email protected] wrote:hi all tried to upload pic but camera has to many pixels


Oh deary, deary me, this is always such a bother. Maximum file size here is 768 kb with a further limitation of something like 1024X680 pixel dimensions. It only takes a moment or two to resize the image using the software that came with your camera or is native on your PC. Images come out of my camera in the 5 Mb range so I do this fairly often.
Russ Newton
Elan +2S (1971)
Elite S2 (1962)
User avatar
CBUEB1771
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1562
Joined: 09 Nov 2006
Location: Boston, Massachusetts USA

PostPost by: garyeanderson » Thu Jun 12, 2008 8:34 pm

instructions are here on this site
http://www.lotuselan.net/forums/viewtopic.php?t=13052

If you want you can get an account on photobucket.com or one of the other photo hosting site and link with
( [img])%20([/img] )
these tags are above the message body where you type in the text.

baring that mail them to me at [email protected] and I'll resize and post either here or photobucket. I am not trying to be an a$$hole, as I don't really need the practice.
Words just don't explain it properly when photos can.
User avatar
garyeanderson
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 3129
Joined: 12 Sep 2003
Location: Massachusetts, U.S.A.

PostPost by: types26/36 » Thu Jun 12, 2008 10:46 pm

For anyone useing M/S XP there s a handy little tool for image resizing on this web page (about halfway down)
http://www.microsoft.com/windowsxp/down ... rtoys.mspx
Brian
64 S2 Roadster
User avatar
types26/36
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 3269
Joined: 11 Sep 2003
Location: U.K.

PostPost by: mct340 » Fri Jun 13, 2008 1:07 am

I just completed a total rebuild on my S4.
Stage 111 engine by Omnitech (John McCoy)
Stromberg to Weber conversion
total drivetrain upgrade to racing spec
you name it I did it
huge $$$$

Result:
engine dyno peak hp 155 @6500rpm
peak torque 148 ft-lbs @4600
chassis dyno max hp [email protected]
max torque [email protected]
mct340
Second Gear
Second Gear
 
Posts: 73
Joined: 08 Oct 2003
Location: Victoria, Canada

PostPost by: steveww » Fri Jun 13, 2008 8:51 am

Just a carb change should not make that much difference as the Webers flow the same as the Strombergs. The main limitation is the flow of the head. The Weber head flows straight from the carb to the cylinder. The Stromberg head has a kink in this flow not to mention that at certain points in the combustion cycle two cylinders are drawing from one carb. However due to the way CV carbs (Stromberg) work the gas flow is quicker which gives the Stromberg engine better torque. The throttle response of the Weber will be better as it has acceleration jets and the Stromberg does not. However with a little tweaking this difference can be largely overcome.

Still want to see some pictures though :wink:
User avatar
steveww
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1849
Joined: 18 Sep 2003
Location: Northamptonshire, England

PostPost by: ppnelan » Fri Jun 13, 2008 9:29 am

BHP = Brochure Horse Power (Graham Arnold) :wink:

:arrow: Matthew
ppnelan
Fourth Gear
Fourth Gear
 
Posts: 739
Joined: 16 Sep 2003
Location: Norfolk, UK

PostPost by: rgh0 » Fri Jun 13, 2008 9:55 am

mct340 wrote:I
Result:
engine dyno peak hp 155 @6500rpm
peak torque 148 ft-lbs @4600
chassis dyno max hp [email protected]
max torque [email protected]



155 hp on an engine dyno at 6500 rpm from a McCoy stage 3 head is about what I would expect from a 1600cc twin cam with a road fuel compression and suitable cams . The chassis dyno number is a little lower than I would expect as the difference is typically around 30 hp from the egnie dyno 47hp is bigger than normal. However lots of factors can influence this difference so its not impossible.

The chassis dyno peak is always lower than engine dyno as near the peak the frinction losses are increasing faster than the engine output so it starts dropping earlier than on an engine dyno. 1200 rpm lower is again a little bigger than i would expect but not impossible. Tyre pressure can make a big difference on a chassis dyno result and if to low greatley increase the losses

All said though its this sort of data that make me ( and others) question the achievement of 132 bhp (either at wheels or flywheel) by just bolting a new carb and add on manifold onto a stromberg head

cheers
Rohan
User avatar
rgh0
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 6277
Joined: 22 Sep 2003
Location: Melbourne, Australia

PostPost by: msd1107 » Fri Jun 13, 2008 10:42 pm

mct340,

What was your engine capacity?

155 hp @ 6500 rpm on a standard 1558 cc TC is a BMEP of 199 psi, 13.7 bar. The torque figure of 148 ft-lbs is a BMEP of 235 psi, 16.2 bar.

These are really surperlative figures. As a point of reference, F1 engines get a little over 200 psi at peak power, 220 at peak torque.

Even a long stroke 1700 cc motor will be at 182/215, still great figures.

David
1968 36/7988
User avatar
msd1107
Fourth Gear
Fourth Gear
 
Posts: 834
Joined: 24 Sep 2003
Location: Hollywood, CA USA

PostPost by: bcmc33 » Mon Jun 16, 2008 2:47 pm

I asked Del for a picture - and this is what I received.
Attachments
Single Weber conversion.jpg and
Brian Clarke
(1972 Sprint 5 EFI)

Growing old is mandatory..........Growing up is optional
User avatar
bcmc33
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1849
Joined: 10 Apr 2006
Location: Aldridge, West Midlands, UK.

PostPost by: steveww » Mon Jun 16, 2008 8:43 pm

Looks interesting. Not sure if the bar just after the carb is a balance tube or not?

Initial thoughts are that there is quite a kink from the carb to the head and this can not help the flow.

IIRC he said he was using a Weber 45 DCOE which about matches the CD175 @ 44.5mm. Can't see that the flow would be much better than a pair of Strombergs. Throttle response may be better due to accelerator pump. However this can be tuned in the Stromberg. Torque may not be as good as the Stromberg due to lower velocity.

Still and interesting solution :?
Attachments
Lotus_elan_3_320pix.jpg and
The best of both worlds
User avatar
steveww
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1849
Joined: 18 Sep 2003
Location: Northamptonshire, England

PostPost by: mct340 » Tue Jun 17, 2008 3:11 am

David,
Bore : 3.250in Stroke : 3.056in
Cyl Vol : 415.44cc Total vol: 101.4ci
Intake valve 1.562 Exh valve 1.312
comp ratio 10.50
combustion space 43.73cc
cam mccoy440_250

All courtesy John McCoy whom we should be very thankful for and keep
sending him work so he stays in business for ever.
Cheers,
Mike
mct340
Second Gear
Second Gear
 
Posts: 73
Joined: 08 Oct 2003
Location: Victoria, Canada

PostPost by: msd1107 » Tue Jun 17, 2008 3:52 am

Thanks for the info, Mike.

I'm sure John has his reasons, but it is interesting he stays with the 1.562' intakes with a long stroke motor. 6500 rpm is definitely at the upper range for that valve size.

If he had gone to the 1.625" valve size, with his cam, peak power might have gone up 4-500 rpm to give you maybe 165 hp.

But I bet you are quite happy with the performance you have now!

David
1968 36/7988
User avatar
msd1107
Fourth Gear
Fourth Gear
 
Posts: 834
Joined: 24 Sep 2003
Location: Hollywood, CA USA

PostPost by: [email protected] » Tue Jun 17, 2008 8:34 am

so theres nothing to be gained on fitting a webber carb ? i can tell you its like calk and cheese, first of all strombergs are crap, , diaphrams that get pin holes , etc , and whats the point of putting a pic of four motor bike carbs on a webber head , on this topic , your not allowed to run the motor bike carbs in the classic sports and saloon car championship, , and further more i know my adapter manifold works , the end
800bhp escort cosworth, 1000bhp nissan skyline , rs200, ,rs 500 ,lotus europa twin cam ,lotus elan s4 rolling road , ecu remaps, powder coating ,like making things that work, do all my own engine work ,worked for cosworth,lotus , porsche, aston martin
[email protected]
First Gear
First Gear
 
Posts: 24
Joined: 09 Jun 2008
Location: lanark
PreviousNext

Total Online:

Users browsing this forum: MarkDa, rgh0, XR40 and 6 guests