Login    Forum    Search    FAQ

Board index » Racing Forum » Fuel Systems




Post new topic Reply to topic  [ 28 posts ]  Go to page 1, 2  Next
Author Message
 Post subject: New Builds
 Post Posted: Sat Sep 22, 2012 7:05 pm 
Offline
User avatar

Joined: Mon Oct 29, 2007 7:07 pm
Posts: 1422
Location: Florida
Being unable to drive at the moment I've been keeping busy with other little projects.
This one is for me to play with on the SB2, or loan out for testing. Race gas or Q16 with a jet change. 2.25 blade, 2.00 venturi, flowed 1516 CFM.

Image


Top 
 Profile  
 
 Post subject: Re: New Builds
 Post Posted: Sat Sep 22, 2012 7:14 pm 
Offline
User avatar

Joined: Mon Oct 29, 2007 7:07 pm
Posts: 1422
Location: Florida
This one is a 2.300 blade, 2.00 venturi based on a QFX body. It flowed 1540 CFM, and will run on a 615"engine in a T/S car on Q16.

Image


Top 
 Profile  
 
 Post subject: Re: New Builds
 Post Posted: Sat Sep 22, 2012 7:28 pm 
Offline
User avatar

Joined: Sat Feb 07, 2009 4:12 pm
Posts: 1215
Location: Adelaide Australia
I note both these carbys have the booster entrance down inside a virtually straight tube air entrance. Humm. The entrance to the booster is already in fast moving air so the entrance pressure is reduced so the booster generation must be reduced. Have you tested for that.


Top 
 Profile  
 
 Post subject: Re: New Builds
 Post Posted: Sat Sep 22, 2012 7:48 pm 
Offline
User avatar

Joined: Wed Apr 19, 2006 8:20 pm
Posts: 5852
Location: N.J.
I see you like those QFX body's Mark =; ...I just got one from Bruce to try with E85...The boosters are in the same location but the top has been extended some..They also take a different banjo..

_________________
Image
running E85
Best ET 8.07
Best MPH 170.71
Barry


Top 
 Profile  
 
 Post subject: Re: New Builds
 Post Posted: Sat Sep 22, 2012 9:14 pm 
Offline
User avatar

Joined: Mon Oct 29, 2007 7:07 pm
Posts: 1422
Location: Florida
I know all about that body you just got... ;-)

Shrinker, the pictures are deceiving. The entrance is about 2.5", the venturi 2.00", the butterfly 2.25" and 2.300. The boosters are down in a little farther than I like, but booster signal is good. I may do some experimenting with the next one on the entrance. Booster signal was 30.5" @ 10.45" H2O underneath, about 52" @ 20.45" H2O


Top 
 Profile  
 
 Post subject: Re: New Builds
 Post Posted: Sat Sep 22, 2012 10:13 pm 
Offline
User avatar

Joined: Sat Feb 07, 2009 4:12 pm
Posts: 1215
Location: Adelaide Australia
How does that booster signal compare to a normal dommy like the one in your signature.


Top 
 Profile  
 
 Post subject: Re: New Builds
 Post Posted: Sat Sep 22, 2012 10:35 pm 
Offline
User avatar

Joined: Sat Feb 07, 2009 4:12 pm
Posts: 1215
Location: Adelaide Australia
I would check the booster signal curve comparison between the 2. The entrance of the booster in the original holley design is in slower air with the tail at the main venturi so that provides close to the maximum energy (at the entrance) to flow to the minimum energy( at the venturi). With the large venturi new one your playing with, the entrance energy is possibly lower than the holley design so the booster curve will more closely follow the main venturi. In other words it should somewhat resemble working like a carby without a booster.
Note that the booster sig doesnt get to double when the vac is( or very close to in your test). That should mean its going to lean out and the emulsion has to be used to blow the fuel rather than trim the AFR by viscosity. I would suspect the design to have to have considerable emulsion air flow. Bit like the NASCAR carbys.
Lets see how it turn out.


Top 
 Profile  
 
 Post subject: Re: New Builds
 Post Posted: Sat Sep 22, 2012 11:39 pm 
Offline
User avatar

Joined: Mon Oct 29, 2007 7:07 pm
Posts: 1422
Location: Florida
Actually the booster signal is almost identical to the 1050 we won with. The signal was lower with an 1150 and 1250 but the same as the 1050. I think the booster placement has something to do with it on rhe QFX body, and when we were working on the challenge carb I thought much the same that emulsion would be higher for correction. It actually ended up close to normal, just needed more jet for the increased airflow with the boosters I used. The 2.300 carb was actually run at BLP last week on an 800+ HP 540, not the optimum carb for the engine but gave me the chance to test it before sending it out with the fuel they are using to get jetting close. We only made two pulls and a stumble test, we made a jet change that put it in a safe range after the first pull and quit. The stumble test was idle to WOT with the dyno holding RPM to around 3000 I think. I was warned the results might hurt my feelings, but despite being over carbed it handled it well. And while it can be a 3 circuit, the intermediates are plugged making it a 2 circuit.


Top 
 Profile  
 
 Post subject: Re: New Builds
 Post Posted: Sun Sep 23, 2012 1:41 am 
Offline
User avatar

Joined: Sat Feb 07, 2009 4:12 pm
Posts: 1215
Location: Adelaide Australia
So the big question is Why is the booster signal the same?


Top 
 Profile  
 
 Post subject: Re: New Builds
 Post Posted: Sun Sep 23, 2012 7:59 am 
Offline
User avatar

Joined: Wed Apr 19, 2006 8:20 pm
Posts: 5852
Location: N.J.
Would it have something to do with the raised lip on the top side?? Kind of like the non HP older style Dominators..

_________________
Image
running E85
Best ET 8.07
Best MPH 170.71
Barry


Top 
 Profile  
 
 Post subject: Re: New Builds
 Post Posted: Sun Sep 23, 2012 8:53 am 
Offline
User avatar

Joined: Mon Oct 29, 2007 7:07 pm
Posts: 1422
Location: Florida
I think is has to do some with the shape of the venturi overall compared to the Holley, and the fact that the booster sits about .400" below the venturi minimum diameter. On the smaller carb I modified the banjo a little to help air flow a little, I need to go back to the flow bench to test between that mod and a stock banjo to see if it made any difference. One thing I want to try in the future is opening up the venturi, and move the venturi point down. Moving the booster up would be nice, but a LOT of work to do. I've had a couple requests to send this one out for testing, so I'll see how it works and then go from there on the next one.


Top 
 Profile  
 
 Post subject: Re: New Builds
 Post Posted: Sun Sep 23, 2012 11:30 am 
Offline
User avatar

Joined: Wed Apr 19, 2006 8:20 pm
Posts: 5852
Location: N.J.
Mark, On the one I have the Banjo sticks out from the edge of the grove that it sits in and it's also a bit loose. Wondering if I should adjust for a better smother fit...Also I noticed that there is no lip from the top side to the bottom of where the Banjo bottoms in the grove like there is in a Holley Dominator.

Also how much of a press fit should there be between the brass pin into the banjo? I have to drill out the banjo to 213 and then drill the end of the banjo where the brass pin fits inside..
I can't do it in my drill press as there is just to much run out so I have to get over to Tony's house so I can use his bridge port....Funny but I see in QF catalog that they make a Banjo with the 213 hole with a full skirt for alky..Are they not available
with out the boosters??

_________________
Image
running E85
Best ET 8.07
Best MPH 170.71
Barry


Top 
 Profile  
 
 Post subject: Re: New Builds
 Post Posted: Sun Sep 23, 2012 11:51 am 
Offline
User avatar

Joined: Mon Oct 29, 2007 7:07 pm
Posts: 1422
Location: Florida
If you go up a little at a time you can drill them by hand, they probably have them drilled but at an increase in cost. Figure .002-.003 press fit, use a brass drift and don't use much force with the hammer. More lighter hits will make it easier to go in and not damage the thin wall of the booster pins.

As far as the banjos I use a taper punch to but dimples in the side of wing opposite the pin where it fits the body to snug it up, once you set the pin that end will be tight.


Top 
 Profile  
 
 Post subject: Re: New Builds
 Post Posted: Sun Sep 23, 2012 11:57 am 
Offline
User avatar

Joined: Wed Apr 19, 2006 8:20 pm
Posts: 5852
Location: N.J.
Thanks Mark ;-)

_________________
Image
running E85
Best ET 8.07
Best MPH 170.71
Barry


Top 
 Profile  
 
 Post subject: Re: New Builds
 Post Posted: Sun Sep 23, 2012 12:10 pm 
Offline
User avatar

Joined: Wed Apr 19, 2006 8:20 pm
Posts: 5852
Location: N.J.
Mark, I was going to make some vent tubes out of brass is that what you did? As it loos like brass and if so what size tube did you use?

_________________
Image
running E85
Best ET 8.07
Best MPH 170.71
Barry


Top 
 Profile  
 
Display posts from previous:  Sort by  
 
Post new topic Reply to topic  [ 28 posts ]  Go to page 1, 2  Next

Board index » Racing Forum » Fuel Systems


Who is online

Users browsing this forum: Bing [Bot], Google [Bot] and 1 guest

 
 

 
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
cron