Carb Help...

[V-8]

Hi guys;
I'm using a Holley 750HP series carb.We notice that carb is not enough for the engine.Anyone suggest me a bigger carb?
Engine spects:
Block:Standard Ford made in 1991, O-ringed
Rotating Assembly: http://www.cnc-motorsports.com/produ...300&CtgID=9059
Balance:Internally Balanced
Carb:750HP series Holley
Intake:Edelbrock Victor Jr(ported&polished)
Ignition:MSD pro billet dist, MSD 6AL, MSD High voltage coil,MSD 3 step retard box
Cam:Comp Cams Mechanic roller 608-614 lift,110 LSA, 0.050 240-246
Rockers:Crane energizer 1.6 ratio and stud girdle
Fasteners:Full ARP and main girdle
Exhausts:Hedman Headers and Flow Masters
Cly Heads:TFS Twisted Wedge heads Full ported and polished,reshaped comb. chambers.
Comp Ratio: 13.1:1
Trans Spects:
TCI Street Fighter transmission
B&M 4000 Stall 8 inc race convertor
Rear-End:
Ford 8 inc, Richmond 3.55 gear,standard axles.
Car weight:3500lbs
Red line:6500rpm
Tires:245/45/17 Kumho's and 275/50/15 BFG drag radials.
E.T.:11.5 and 120 mil.
Gas:98 octane and %30 tolien for one tank.
FIRST QUESTION:Holley or Demon?
SECOND QUESTION:4150 series or Hp series?
THIRD QUESTION:Which cfm i must choose?
Note:I'm using Nos pro shot fogger 250hp with alcohol.
THANKS...

[blykins]

Cubic inches?

[V-8]

408w,sorry...

[blykins]

My choice would be a Holley 950HP setup for alcohol.....you can jet it down a little if you need to.

I'm using a Mighty Demon 750 on my 425ci Windsor.....we found it was a little shy of perfect too. Kept having to jet it up.....

What's wrong with the Holley? Not flowing enough air or are you running the biggest jets you can in it?

[V-8]

408w,sorry...

[V-8]

Engine running with 98 octane+ %30 toluen and using nos with alcohol.

[V-8]

Engine cid is 408w.I have no fuel pressure problems.I have only octane problem,i can't buy more than 98 octane in Turkey so i add %30 toluen but i'm still at 18* timing
First i ordered Holley Jet Assortment Pack and started to jetting but it didn't get enough.So i must buy a bigger carb and one of my friend wants to buy my 750HP carb
Plugs have a lean mixture

[trularin]

Have you done a search for this topic in the posts?

There is a lot of information including formulas and advice.

[RACER X #99]

825 CFM

[V-8]

Originally posted by trularin


Have you done a search for this topic in the posts?

There is a lot of information including formulas and advice.

No! Where are they?

[Frank Messina]

Just curious, how did you determine that the carb wasn't big enough? Is your carb a double pumper or vacuum secondary?
Frank

[tpiini]

You say you can only run 18 degrees of timing, or did I misunderstand? If true, THAT'S your problem. Until you can get enough octane in to keep it from detonation at a real ignition advance, you can't even think about tuning your carb.

But I only hava an anonymous internet opinion.

If it was MY money, I'd be on the phone to Barry Grant & inquire about their Demon lines.

[Big-Foot]

V-8 - You have a whole wagon load of troubles here.

With a 3500# car your 8" rear end will grenade very soon if you ever make all the HP your engine is capable of and you have tires that will put it to the ground.

With a 13.1:1 Compression ratio - you need 110 Octane gasoline.
A 30% (Thirty percent) by volume mixture of Tolulene is WAY too much. At the most you would run about 5%. It might bring you up to something that would approximate 110 Octane. The specific gravity of your octane booster is such that your jetting is way off the mark.

18 degrees initial advance is actually quite a bit.

The size of the carb has absolutely nothing to do with being lean in your case (or most others for that fact). It is most likely running lean because you have changed the fuel to the point of making it flow differently (different specific gravity).

You noted that you are running a 250 shot of nitrous with Alcohol - if you have ready access to volumes of Methanol - I would switch the fuel system over entirely to alcohol and run with it. We've fielded cars with 14:1 CR un-restricted with Alky with no problem. On the restrictor plate engines we have run as high as 15.5:1.

CFM - I would chose 830/850 CFM Holley.

Good luck!

[V-8]

Originally posted by Frank Messina


Just curious, how did you determine that the carb wasn't big enough? Is your carb a double pumper or vacuum secondary?
Frank

It is double pumper.Plugs have a lean mixture.

[cuda66273]

Wow, this is the strangest post I've ever seen....I wouldn't touch this with a 20' foot pole and I doubt BG will either.

You need to get the right fuel and quit playing chemist before you blow it or yourself up.

Running on gas and Tolulene adding nitrous and enriching the circiut with alcohol, no way this is a joke of some sort.

...never mind I'm not going to say it...

[SCOBRAC]

I'd run a pair of 1000 cfm Dominators on the engine you describe, but then you aren't me.