Carb fitted

Carl · Post by **Carl** » Tue May 21, 13 2:16 pm

The new carb and manifold are on Holley 850DP and air gap manifold. Had a stumble issue but I have sorted that out now and the whole set up has made a huge improvement over the 750 vac sec.

Dave-R · Post by **Dave-R** » Tue May 21, 13 2:34 pm

Looks really good.

They are damn good manifolds those.

TW71 · Post by **TW71** » Tue May 21, 13 5:13 pm

That looks nice

That will wake it up alright!

Carl · Post by **Carl** » Wed May 22, 13 9:33 am

Cheers guys.

Yes certainly woke it up a bit.

db · Post by db » Wed May 22, 13 9:37 am

I'll bet it's made quite a difference!!
I'm hoping to get my 750dp on soon, then try out an 850...

Dave81 · Post by **Dave81** » Wed May 22, 13 12:41 pm

Carl wrote:Cheers guys.

Yes certainly woke it up a bit.

Interested to hear more info Carl?

Is the improvement across the whole range or at a certain point (Low end grunt/high end HP).

Has it got a faster pickup off the throttle compared to the 750.......?

Easier to lose traction............

?

Carl · Post by **Carl** » Wed May 22, 13 12:54 pm

Not had a chance to take it out and open it right up i.e. Motorway, but it def seems to have improved the low end and mid range acceleration, it feels more responsive for sure.

Dave-R · Post by **Dave-R** » Wed May 22, 13 12:58 pm

When a DP carb is tuned right it has a much sharper throttle response and no hesitation when you floor it. That is what you will feel the benifit of in the main.
It probably will not make any difference to how the top end power feels. Unless the previous carb was too small for the engine.

Guy · Post by **Guy** » Wed May 22, 13 1:11 pm

Dave81 · Post by **Dave81** » Wed May 22, 13 1:44 pm

Dave wrote:When a DP carb is tuned right it has a much sharper throttle response and no hesitation when you floor it. That is what you will feel the benifit of in the main.
It probably will not make any difference to how the top end power feels. Unless the previous carb was too small for the engine.

Interesting......In that case is there a minimum tune level in which your'd feel the real benefit of a DP carb over a say a normal 4 barrel Holley?

Understand thats open ended about which engine, and what you class as a certain level of tune, so may not be a straight forward answer!

Pete · Post by **Pete** » Wed May 22, 13 1:47 pm

DP (as Dave says) can give sharper throttle response and is easier to tune out flat spots.

A wrong DP set up is about as good as a wrong Vac Sec set up.

No silver bullet here - you have to work all the tuning issues through on a "per car" basis.............

Dave-R · Post by **Dave-R** » Wed May 22, 13 1:56 pm

A vacuum secondary carb can be tuned just as well but by their nature they will always have a slight hesitation and slower throttle response. You can minimise it dramatically with tuning but it will always be there.

This is not dependant on what engine the carb is fitted to. Although vac sec carbs do work better on a dual plane intake.

Personally I would not use a vac secondary carb on an engine unless I was worried the carb was too big for the application.