Tuning triple 45 DCOE webers

grb184

Club Member
Hi all,

I am based in Hertfordshire and am looking to get my 260z retuned as it is becoming lumpy on cold start and the MPG has fallen away drastically (down to 11mpg!). I am currently running the following set up:

2.8 with ported and polished head
Fast road cam
Triple Weber 45 DCOE carbs with the following:
Choke: 32mm
Main: 115
Idle: F9 60
Air corrector: 200
Emulsion F16
Pump jet: 40

When this was last tuned on a rolling road (only 2 years ago) she was pushing out 165bhp

Looking for a recommendation somewhere in the South East for someone to give her a look over and retune, any suggestions/recommendations please.

Thanks
Graham
IMG_0268 (002).JPG
 

jonbills

Membership Secretary
Site Administrator
If you can make it up to Northampton, I'm sure I could help you get it back to where it should be.
 

atomman

Club Member
I will dig out my carb set up spec's and post it up for you to compare , I'm running 40's on my bored out L28 , (just under 3.0 now) with N42 polished and ported head with a rally spec cam etc

My first thought though why choke 45's all the way down to 32 ? ( 45's might be all you have though ) 40's flow better up to 36mm chokes
 

Albrecht

Well-Known Forum User
If it was running OK before - and you were happy with it - then I wouldn't think messing around with jets and venturis is going to help cure the immediate problem (even if there IS 'more' to be had from your engine with larger venturis etc).

Surely this falling away of performance is something more fundamental? Weber 45DCOEs don't 'go out of tune' on their own.
 

jonbills

Membership Secretary
Site Administrator
If it was running OK before - and you were happy with it - then I wouldn't think messing around with jets and venturis is going to help cure the immediate problem (even if there IS 'more' to be had from your engine with larger venturis etc).

Surely this falling away of performance is something more fundamental? Weber 45DCOEs don't 'go out of tune' on their own.
I was thinking it's something easy, like cold start on, or out of balance.
 

hamid

Forum User
Hi all,

I am based in Hertfordshire and am looking to get my 260z retuned as it is becoming lumpy on cold start and the MPG has fallen away drastically (down to 11mpg!). I am currently running the following set up:

2.8 with ported and polished head
Fast road cam
Triple Weber 45 DCOE carbs with the following:
Choke: 32mm
Main: 115
Idle: F9 60
Air corrector: 200
Emulsion F16
Pump jet: 40

When this was last tuned on a rolling road (only 2 years ago) she was pushing out 165bhp

Looking for a recommendation somewhere in the South East for someone to give her a look over and retune, any suggestions/recommendations please.

Thanks
Graham
View attachment 52615
Hi ,
I’m also in the same area and went back to Fourway engineering in Kent.
Give them a try , they are very good and fast turn around for any modification etc .
 

richiep

Club Member
As has been noted, Webers and other sidedrafts with fixed jetting don't really go out of tune on their own; issues about "tuning" tend to actually be things like balance between the carbs getting disturbed, slippage in the linkages, maybe carbs needing a clean out, etc.

Could timing/ignition be an issue here? Check whether the dizzy is properly tight for a start. Issues with cold start performance and mpg could easily be associated with timing setup/dizzy position.

Separate issue - you should be able to get more out of the engine though, even when it was running okay. 175-180 rwhp/200fwhp would not be unreasonable to expect.
 
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