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#2414858 - 12/07/17 04:17 PM Re: Another Carb question... [Re: Thumperdart]
Benforsp Offline
member

Registered: 07/06/05
Posts: 152
Loc: Bradenton, FL
Originally Posted By Thumperdart
You have to to in order to have a base tune and to know what needs to be changed to bring it around to your cars needs...........no other way........ thumbs


Thumper,

What all is involved in this and what specialty tools are needed?

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#2414883 - 12/07/17 05:04 PM Re: Another Carb question... [Re: Benforsp]
Thumperdart Offline


Registered: 07/12/04
Posts: 18692
Loc: State of confusion
We need to talk, too much to type..........
_________________________
72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB for videos and lots of carb pics......760-900-3895.....

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#2414904 - 12/07/17 05:32 PM Re: Another Carb question... [Re: Thumperdart]
BradH Offline
I Live Here

Registered: 01/30/03
Posts: 13723
Loc: Valhalla... eventually
Originally Posted By Thumperdart
We need to talk, too much to type.......... with one finger

haha
_________________________
This space intentionally left blank... except where it says: "This space intentionally left blank"

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#2414948 - 12/07/17 07:16 PM Re: Another Carb question... [Re: Benforsp]
fast68plymouth Offline
I Live Here

Registered: 01/20/03
Posts: 10764
Loc: So. Burlington, Vt.
Quote:

-> 440-ish cubes with "big" heads that work better on 500+"
-> moderate CR
-> 260+ at .050" street roller
-> limited stall speed
-> street-tuned(?) carb w/ 1.56 venturi & downleg boosters


Those are my thoughts as well.

1.56 venturi downleg carbs can be a real challenge to "tune the bog out of".

IMO, I think a main body swap to something with a smaller venturi would ultimately yield better results(I'd probably use a 1.400 x 1.750)....... But if I were trying to work around that combo, I would expect to have to run fairly large squirters, and probably a 50cc pump/cam on the secondary side, and I would absolutely ditch the 2.5 pv.
You want to get a head start on the main circuit enrichment when going to wot...... It would get a 6.5 if I were messing with it.

There is a lot of plenum and runner volume in that combo, and not a lot of cubes generating signal.......... It's going to need a lot of help(pump shot) to give the motor something to work with until the main circuit is activated.

Not what you asked, but there is some performance left on the table with that cam, in that combo.
_________________________
68 Plymouth Satellite, 383, stock 906's, 3550lbs, 11.18 @ 123, 1.51 60'
WD- Comp Cams / Indy Cylinder Heads

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#2414956 - 12/07/17 07:34 PM Re: Another Carb question... [Re: Benforsp]
Dadodgekid Offline
member

Registered: 03/26/07
Posts: 58
Loc: Palm City, FL
whats the fuel pressure set to...

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#2414966 - 12/07/17 07:52 PM Re: Another Carb question... [Re: BradH]
Thumperdart Offline


Registered: 07/12/04
Posts: 18692
Loc: State of confusion
Originally Posted By BradH
Originally Posted By Thumperdart
We need to talk, too much to type.......... with one finger

haha


You know me too well...............lol
_________________________
72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB for videos and lots of carb pics......760-900-3895.....

Top
#2415165 - 12/08/17 09:19 AM Re: Another Carb question... [Re: fast68plymouth]
Benforsp Offline
member

Registered: 07/06/05
Posts: 152
Loc: Bradenton, FL
Originally Posted By fast68plymouth
Quote:

-> 440-ish cubes with "big" heads that work better on 500+"
-> moderate CR
-> 260+ at .050" street roller
-> limited stall speed
-> street-tuned(?) carb w/ 1.56 venturi & downleg boosters


Those are my thoughts as well.

1.56 venturi downleg carbs can be a real challenge to "tune the bog out of".

IMO, I think a main body swap to something with a smaller venturi would ultimately yield better results(I'd probably use a 1.400 x 1.750)....... But if I were trying to work around that combo, I would expect to have to run fairly large squirters, and probably a 50cc pump/cam on the secondary side, and I would absolutely ditch the 2.5 pv.
You want to get a head start on the main circuit enrichment when going to wot...... It would get a 6.5 if I were messing with it.

There is a lot of plenum and runner volume in that combo, and not a lot of cubes generating signal.......... It's going to need a lot of help(pump shot) to give the motor something to work with until the main circuit is activated.

Not what you asked, but there is some performance left on the table with that cam, in that combo.


Fast,

The carb had 6.5's in it and I can put them back in no sweat. I knew the cam was pretty big but had talked to some folks and they suggested it would be suitable, but I would consider other options, what might you advise?

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#2415169 - 12/08/17 09:24 AM Re: Another Carb question... [Re: Dadodgekid]
Benforsp Offline
member

Registered: 07/06/05
Posts: 152
Loc: Bradenton, FL
Originally Posted By Dadodgekid
whats the fuel pressure set to...


Kid,

The fuel pressure is 6.5-7 PSI. I run an electric pump with a return style fuel system with -8 lines.

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#2415212 - 12/08/17 10:48 AM Re: Another Carb question... [Re: Benforsp]
fast68plymouth Offline
I Live Here

Registered: 01/20/03
Posts: 10764
Loc: So. Burlington, Vt.
It would require a conversation before I would recommend any other cam, but I think getting rid of some seat timing would be a step in the right direction.

You said "pv's"....... If you're still running one in the secondary side, remove it and replace with a plug....... And jet up accordingly(around 8 sizes).
_________________________
68 Plymouth Satellite, 383, stock 906's, 3550lbs, 11.18 @ 123, 1.51 60'
WD- Comp Cams / Indy Cylinder Heads

Top
#2415239 - 12/08/17 11:30 AM Re: Another Carb question... [Re: Benforsp]
Thumperdart Offline


Registered: 07/12/04
Posts: 18692
Loc: State of confusion
Originally Posted By Benforsp
Originally Posted By Dadodgekid
whats the fuel pressure set to...


Kid,

The fuel pressure is 6.5-7 PSI. I run an electric pump with a return style fuel system with -8 lines.


Still waiting for a call...........lower the pressure to 5.5 max IF you run .120 needle n seats which you should....... callme
_________________________
72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB for videos and lots of carb pics......760-900-3895.....

Top
#2415277 - 12/08/17 12:53 PM Re: Another Carb question... [Re: Benforsp]
Cab_Burge Offline
I Win

Registered: 08/23/03
Posts: 30798
Loc: Bend,OR USA
Originally Posted By Benforsp
Originally Posted By BradH
You still haven't given any details of the cam or the carb's current tune. That doesn't make it any easier to try and help.

The 0-82951 is the "Street HP", right? Check the actual venturi diameter and see if it's 1.38" or 1.56" I've seen conflicting specs, depending upon when the carb was made I guess. The tune would likely vary quite a bit depending upon which size it is.

I have no first-hand experience w/ the "Street HP" stuff. I'd hope that they're "flexible" enough to be tuned to work w/ your combination.


http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=739&sb=1

Installed straight up with 1.6 ratio rockers to bring the lift up.
Cam Detail....

Did you degree the cam or did you install it with the dots "straight up" ? If not degreed you should do that now twocents
I would advance it so the intake lobes are from 107 to 105 max lift after top dead center up
I've ran a very similar cam (260@.050 int., 266@.050 ex. ground on a 108 LC installed two degrees advanced on the intake lobes)) Comp solid roller with 1.6 ratio rockers, no bog even with a six pack set up after I had to sort it out.
I had another bracket motor with a Holley 80496 950 HP on a TM7 intake with ported 906 heads and a bigger Crane solid roller and it never bogged ever, that cam was advanced 4 degrees work


Edited by Cab_Burge (12/08/17 12:54 PM)
_________________________
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

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#2415298 - 12/08/17 01:46 PM Re: Another Carb question... [Re: Cab_Burge]
Benforsp Offline
member

Registered: 07/06/05
Posts: 152
Loc: Bradenton, FL
Originally Posted By Cab_Burge
Originally Posted By Benforsp
Originally Posted By BradH
You still haven't given any details of the cam or the carb's current tune. That doesn't make it any easier to try and help.

The 0-82951 is the "Street HP", right? Check the actual venturi diameter and see if it's 1.38" or 1.56" I've seen conflicting specs, depending upon when the carb was made I guess. The tune would likely vary quite a bit depending upon which size it is.

I have no first-hand experience w/ the "Street HP" stuff. I'd hope that they're "flexible" enough to be tuned to work w/ your combination.


http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=739&sb=1

Installed straight up with 1.6 ratio rockers to bring the lift up.
Cam Detail....

Did you degree the cam or did you install it with the dots "straight up" ? If not degreed you should do that now twocents
I would advance it so the intake lobes are from 107 to 105 max lift after top dead center up
I've ran a very similar cam (260@.050 int., 266@.050 ex. ground on a 108 LC installed two degrees advanced on the intake lobes)) Comp solid roller with 1.6 ratio rockers, no bog even with a six pack set up after I had to sort it out.
I had another bracket motor with a Holley 80496 950 HP on a TM7 intake with ported 906 heads and a bigger Crane solid roller and it never bogged ever, that cam was advanced 4 degrees work


Cab,

I had thought about installing it advanced and regret not doing so at this point. The cam was degreed.

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#2415303 - 12/08/17 01:54 PM Re: Another Carb question... [Re: Benforsp]
PorkyPig Offline
mopar

Registered: 08/31/06
Posts: 567
Loc: home in bed
Originally Posted By Benforsp
Originally Posted By Thumperdart
You have to to in order to have a base tune and to know what needs to be changed to bring it around to your cars needs...........no other way........ thumbs


Thumper,

What all is involved in this and what specialty tools are needed?

How much carb tuning experience do you really have? It sounds like you may be in over your head.

Top
#2415304 - 12/08/17 01:57 PM Re: Another Carb question... [Re: Thumperdart]
Benforsp Offline
member

Registered: 07/06/05
Posts: 152
Loc: Bradenton, FL
Originally Posted By Thumperdart
Originally Posted By Benforsp
Originally Posted By Dadodgekid
whats the fuel pressure set to...


Kid,

The fuel pressure is 6.5-7 PSI. I run an electric pump with a return style fuel system with -8 lines.


Still waiting for a call...........lower the pressure to 5.5 max IF you run .120 needle n seats which you should....... callme


I tried! No Answer.

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#2415327 - 12/08/17 02:47 PM Re: Another Carb question... [Re: Benforsp]
fast68plymouth Offline
I Live Here

Registered: 01/20/03
Posts: 10764
Loc: So. Burlington, Vt.
Quote:
I had thought about installing it advanced and regret not doing so at this point. The cam was degreed.


If the cam was installed as per the cam card in the link you posted, then it's installed 4deg advanced.
The advance is ground into the cam.

Advancing it "more" isn't going to cure your problem.
_________________________
68 Plymouth Satellite, 383, stock 906's, 3550lbs, 11.18 @ 123, 1.51 60'
WD- Comp Cams / Indy Cylinder Heads

Top
#2415653 - 12/09/17 08:15 AM Re: Another Carb question... [Re: Benforsp]
Tommy D Offline
enthusiast

Registered: 10/02/08
Posts: 389
Loc: Harleysville, PA USA
It was mentioned earlier to check the float levels. I did not see a response where that was checked. Where do you run the float level?

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