twin 40's

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algtj · #1 Post by **algtj** » Thu Jan 05, 2006 7:12 am

Have been offered a set of twin 40 webbers on pinto manifolding, how easy is it to come across a manifold suitable for a Sprint and how much should I pay. I might stick them on the Manta yet........<img src=http://www.ezboard.com/intl/aenglish/im ... /devil.gif ALT=":evil">

SMIFTER · #2 Post by **SMIFTER** » Thu Jan 05, 2006 10:01 am

They come up from time to time on ebay and go for around £100 to £150. The last time i looked new price was £250 ish if you can find someone stocking them. 
 
Regardless of what car you fit them too you'll need to budget rejetting and a rolling road tune - typically £250. 
 
Well worth it though on a Sprint.

<a href="http://www.smifter1971.pwp.blueyonder.c ... >Smifter's Dolomite Sprint Website</a> 
 
Featherweight 1974 Dolomite Sprint - Soon to be XE'd, NOS'd, Megasquirted and 5 linked Lash up to scare myself (and my wallet) senseless 
 
2004 Smart Roadster (company car!!) - 698cc of turbo'd adrenaline fuelled rollerskate - destined to classic status thanks to Daimler Chrysler bean counters. 
 
1997 Audi A4 2.6 to chill out after the above and fill with baby products..... 
 
2005 Trek 1400 (ok its not a car but still fast) - 
a bit like Lance Armstrong but slower and fatter

KWM338R · #3 Post by **KWM338R** » Thu Jan 05, 2006 2:23 pm

are twin 40's upto the job on a Sprint with an STR91 cam? I'm in a dilema as to which route to go, i.e. HS8's, 40's (cos they seem more plentiful) or hold out for some more cash and get some 45's. Never had webers so wouldn't know where to start with them where as I can find my way round SU's OK. 
 
cheers 
 
Mark

1979 Dolomite Sprint 
1972 TR6 (now breaking for spares to fund the Dolly) 
1993 Mazda Protege ($250 Winter Hack) 
2000 Mazda MPV (For Sale)

SMIFTER · #4 Post by **SMIFTER** » Thu Jan 05, 2006 2:37 pm

No. 
 
40's are good for low end torque on standard engines and very mild cams around 150/160BHP. I did run mine on 40's with a Standard engine and it was great below 5500rpm - but the STR91 is more about top end and should give 175BHP ish - you'll need 45's to maximise its potential. 
 
 
G

KWM338R · #5 Post by **KWM338R** » Thu Jan 05, 2006 4:11 pm

Thanks Graeme, 
 
do you have any knowledge of how HS8's will perform with the afore mentioned cam? 
 
cheers 
 
Mark

1979 Dolomite Sprint 
1972 TR6 (now breaking for spares to fund the Dolly) 
1993 Mazda Protege ($250 Winter Hack) 
2000 Mazda MPV (For Sale)

Carsreunited · #6 Post by **Carsreunited** » Thu Jan 05, 2006 4:28 pm

Its more about the choke sizes available. Focusing on 40/45/48's and a common mistake is that people think that the bigger number will give you the most power. There is quite a crossover with 45's and 40's in terms of the different jet permutations. 
 
No doubt 45's will give you greater flexibility the more you advance the state of tune of your engine. 
 
I'll try and find a link of what I mean that illustrates this. 
 
Oh and the intake manifold appears from time to time. I bought one for a friend 6 months ago of the bay for £95. Seen some go for £160+ but I'd wait for a more sensibly priced option to come up.

SMIFTER · #7 Post by **SMIFTER** » Thu Jan 05, 2006 6:27 pm

Your right Scott - its the chokes that are a limiting factor but with 40's I think 36mm is the biggest you can go to, with 45's you can go to 40mm but there is an overlap of sizes. 
 
I think 38mm chokes were used on my 45's with the STR91. 
 
G

bodgerben · #8 Post by **bodgerben** » Thu Jan 05, 2006 9:53 pm

work very well with a STR91 - I've used those before (on a bored out standard inlet manfold), and the beauty of SU's is you cannot over choke the engine. 
The works cars were running HS8's and 175bhp - I don't think the works cars ever used 45's going for 48's when ultimate power was needed (and a different cam). You should be able to get as much power from HS6's as you can from 40's, apart from the wonderful noise 40's won't give you much power difference over a good set of well setup HS6's, same goes for HS8's and 45's. Throttle response is different - I've always found Webers/Dellorto's a bit better, but I never got around to playing with different SU damper springs and lighter oils. 
 
I forget what needles I used - but whatever the TriumphTune guys said - it was a long time ago. I think HS8's on a Sprint look the bees knees. 
 
 
 

Ben 
 
<a href="http://www.dollysprint.com">www.dollysprint.com</a>

Carsreunited · #9 Post by **Carsreunited** » Thu Jan 05, 2006 10:43 pm

This illustrates my point. 
 
I'm ashamed to say I don't know my jet sizes on the 48's<img src=http://www.ezboard.com/intl/aenglish/im ... rassed.gif ALT=":o"> 
 
<a href="http://hometown.aol.com/dvandrews/webers.htm" target="top">hometown.aol.com/dvandrews/webers.htm</a>

algtj · #10 Post by **algtj** » Fri Jan 06, 2006 7:59 am

Now there's a thought..... 
Enlighten me on what HS8's were bolted on. As I am not too bothered about induction noise. 
I am thinking this would be a cheaper way to go! <img src=http://www.ezboard.com/intl/aenglish/im ... /happy.gif ALT=":D">

davepoth · #11 Post by **davepoth** » Fri Jan 06, 2006 10:29 am

Usually a reamed out HS6 manifold these days, but I think there was a proper ST manifold available.

KLJ895W · #12 Post by **KLJ895W** » Fri Jan 06, 2006 11:52 am

I think Al meant what cars were they fitted to. Jaguars is the answer. XJ6s from the early 70s, possibly late 60s. They come up on eBay fairly often, but keep going for more than I'm prepared to pay. If you have deep pockets you could buy them from <a href="http://www.burlen.co.uk/" target="top">Burlen</a> or from <a href="http://www.su-carbs.co.uk/" target="top">Andrew Turner</a>. 
 
If you buy second hand, make sure they aren't from a Rover as these only have 90thou jets. Best way to check is to get the serial number from the seller and check on Burlen's database. 
 
David

Carsreunited · #13 Post by **Carsreunited** » Fri Jan 06, 2006 4:14 pm

Al, I'm quite friendly with a guy who fixes and breaks jags. Do you want me to ask for you?

KWM338R · #14 Post by **KWM338R** » Fri Jan 06, 2006 4:57 pm

Hello Scott, 
 
could you ask your mate how much he wants for a pair of HS8's. i can't find any in the USA, i think the jags here had strombergs. I see them on ebay.uk occasionally but have not had any luck winning any. 
 
Cheers 
 
Mark 
 
msellers (at) mestek.com

1979 Dolomite Sprint 
1972 TR6 (now breaking for spares to fund the Dolly) 
1993 Mazda Protege ($250 Winter Hack) 
2000 Mazda MPV (For Sale)

Carsreunited · #15 Post by **Carsreunited** » Fri Jan 06, 2006 5:23 pm

Just left a message for him. Will get back to you.

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