Thinking about switching intakes....

blykins · #1 (**permalink**) 03-25-2005, 10:34 AM

When I built my engine, Comp Cams advised me to use a cam that's a little outta range for my Vic Jr intake. I have peak horsepower at 5400 and peak torque at 4500.

I can either switch cams to a bigger cam or change intakes....I know which one would be easiest.....but I don't know how much hp it will take from me.

I was thinking on ditching the Vic Jr. single plane intake and replacing it with an air gap dual plane or a Torker single plane....something with a little lower rpm range.

Has anyone done this? How much hp did you lose....and did you gain any torque?

I'm at 484hp and 500 lb-ft right now.....really hate to see that 484 dwindle down.

Sydney · #2 (**permalink**) 03-25-2005, 04:57 PM

Hey blykins,

You might have some trouble getting an Airgap manifold to fit in the Shell Valley. I have a fine line between hood clearance and ground clearance with the RPM Performer manifold. I think the Airgap is a tad taller. I can't remember how much though.

Sydney

blykins · #3 (**permalink**) 03-25-2005, 05:38 PM

Hey Syd...

The air gap manifold is a lot lower than my Vic Jr. The Vic Jr. is a higher rise single plane....it sits up pretty high.

I just don't know what to do yet....I do know my cam isn't allowing me to take advantage of the heads and the intake....The intake and cam are around the same price...and I can reuse my roller lifters and valve springs....

Just don't know what to do...like I said...I know which one would be an easier swap, but I'd say the next cam up from what I got would really turn the engine on.

Right now I'm using a Comp Cam hydraulic roller with a 230 degree duration and a .544 lift. For some reason, Comp Cams recommended this cam to me....I went ahead and took their advice even though the specs say the range tops out at 6000 rpm.

The next cam up is for higher revs...up to 6500....and would probably take advantage of the intake. It's a 244 degree duration and a .576 lift.

ENTDOC · #4 (**permalink**) 03-25-2005, 07:03 PM

can't help but think that you would be happier with the cam change. It sounds like you built your motor for high revs,if you dumb it down by going the easy way out instead of what you really want ,you will regret it later. chuck

Sydney · #5 (**permalink**) 03-25-2005, 07:26 PM

I guess the big question is, are you going to be playing mostly on the street, or the track? That might help with the decision.

Man, I have to know.... How much hood clearance do you have with your current setup?

Sydney

Perf. Eng. Eric · #6 (**permalink**) 03-25-2005, 10:08 PM

On our Dyno, we have only seen a small drop in peak HP. (about 7-10) , but the torque curve was sweet!!! For the cam you have ,I think the Air Gap is the manifold I would use. We have gone to the Air Gap on all of our 302 stroked and non-stroked engine packages for our Cobras. We will also be giving our customers the option of an Air Gap on our 351 W and 460 based engines also. Hope this helps.

blykins · #7 (**permalink**) 03-26-2005, 01:18 PM

Eric, did the torque go up.....or did the average just raise a little bit across the rpm range?

Syd....I'm using a Vic Jr. intake, Demon 750 carb....and a K&N 14" drop base air cleaner. There's about an inch clearance between the hood and the air cleaner.....

But I also have my motor mounts turned upside down to drop the engine down a little further...

trularin · #8 (**permalink**) 03-26-2005, 01:52 PM

May I suggest you do this after the car is done and you have nothing left to spend your money on.

You are getting married...right?

blykins · #9 (**permalink**) 03-26-2005, 06:05 PM

Oh c'mon Tru....don't kill my spirit buddy.....

rdorman · #10 (**permalink**) 03-27-2005, 06:16 AM

I am going to back Eric up on the Air gap. Practically a something for nothing intake. The torque curve will generally be up across the board. If I was doing nothing but drag racing, Victor (it does make a few more ponies), for everything else, I would use and air gap. I just wish they made one for me! Frankly, I am supprised at all the shops that put on the Victor for motors that will not be strickly for racing.
Rick

Perf. Eng. Eric · #11 (**permalink**) 03-27-2005, 06:43 AM

The peak torque was about the same. The torque curve was nice and flat,but he best part is, the peak torque came in at a lower RPM. That makes for a good driver.

jhein · #12 (**permalink**) 03-27-2005, 08:06 AM

I made this exact change on my Perf. Eng built 351W. I don't have any before/after dyno results but the change accomplished what I wanted from a drivability standpoint. The car has just as much seat of the pants pull as ever, if not more. There is no discernable loss in top end (up to 6000 rpm), and low end drivablility is much better.

As for hood clearance I don't think that the RPM Air Gap is much lower than the Vic jr, if at all. The standard RPM is, but not the air gap. If hood clearance is an issue I'd look into that.

John
spf1421

blykins · #13 (**permalink**) 03-27-2005, 12:43 PM

If it's the same height or lower, I'm fine....if it's taller, I may have to do some mods....

SVMCOBRA · #14 (**permalink**) 03-27-2005, 02:35 PM

Bly, I could not run the Victor Jr on my car, although I never thought about turning the motor mounts upside down. I still had to do some mods to my hood to run my Cobra oval air cleaner with a Torker 2 intake.
Ray Hedden

blykins · #15 (**permalink**) 03-27-2005, 02:44 PM

I talked to Dana at Shell....he said that people often just turn them upside down.....I put another bead of weld on the backside....then bolted them in. I think it ended up sitting a little too low like that...so I shimmed under them. I have plenty of clearance with my Vic Jr. and drop base air cleaner.