Weber selection and initial jet tuning

[blodi]

Ill work on the fuel height. I double checked them when I got home...front carb was ~28mm and the rear two were ~30mm. 

Here is a pull I did today just fwiw.......F2 140/240 and 65 exhaust jets.........

6518 by blodi, on Flickr

[240260280]

For information: Here is a WOT dyno run for a  Datsun 4 Cylinder with A15 engine and dual 45DCOE with 32mm chokes.  A/F ratio shape from start to 6000 seems similar to yours but with 4.5  point spread. 

 

[blodi]

^Did they say if that was normal or not? 

Forgot to mention I have had an exhaust manifold gasket leak and now it sprung a second leak today.  Ordered a replacement gasket and need to install that before I proceed. 

[240260280]

No need to rush.

 

They did not discuss the a/f on the site. It was a race site so I am surprised to see this wide range of leaner excursions to 14.

[blodi]

I found this. L28 stroker with triple 45s making over 210at the wheels ......

[240260280]

The A15 has 32mm chokes. You tested 34mm, 35mm and 36mm with the same shape of wot run so it seems independent of nearly every parameter. Hopefully higher fuel level will help.

Edited June 6, 2018 by 240260280

[blodi]

Another one with triple Weber’s..... maybe the dip is “normal”? 

[240260280]

4 minutes ago, blodi said:

Another one with triple Weber’s..... maybe the dip is “normal”? 

 

Possibly but it does not happen on 40's.

Can you re-post the link above in post #305?

[blodi]

Sorry, the pics didn't post. Full thread I found is here...

http://forums.hybridz.org/topic/123487-compare-your-dyno-sheets-here/

Mainly turbo cars, but the ones I referenced above was the post by "AZGhost623" on page one and "Leon" on page 3. 

[240260280]

Thanks! They all have the wonky shape. Even the Stroker with 38mm chokes!

Super rich dip 3k to 4k then leaning on the top end.

 

 

 

 

 

DCOE 45'S - (End of day settings at dyno shop - 38mm Choke | 145 MAIN | 160 AIR | 65F9 IDLE | F11 )

 

 

 

 

[blodi]

So if we kinda say that its "normal" to have that shape to the overall pull (like I've said, the car generally pulls nice and runs great on all these setups...fairly imperceptible to my butt dyno)...the flattest...and closest to the 12.5-13.0 range seems to be either the f16 160/230 combo...

 

or the F16 155/225 combo.....

[240260280]

I thought about this for an hour before falling asleep.  It is troublesome.  This same shape seems to be independent of E-tubes, choke  size, jet size, fuel level (as I believe Leon runs 25mm and you are running ~29mm) and engine size. It happens on the 2.55litre Equivalent A15 and on >3.0litre Strokers!

 

There has to be another parameter no one has addressed.. So I remembered something from Passini ... the Aux Venturi.  I'll do more research and if it is a lead then I'll buy a set and ship to you.