Comp Polymers Intake

A polymer box by its self is overkill for a stock engine. No point in replacing it when the restriction is in the lower intake. The stock heads are more of a restriction than the stock upper.

agreed with the above.. also the intake is ment for boosted or nitrous applications.. it gets rid of the extra runners and gets a more direct approach to the lower... its a waste of money without running some kind of boost or nitrous

I have heard a lot of people say it kills low RPM power because of the short runners.
what do think would result if you had a cnc aluminum 2" spacer made? would you gain more HP throughout a larger range, or is that just dumb?

I just like the price tag, would it be possible to run 2 of those 1" spacers on top of each other?,.....
im not thinking so

GREYFOX4INCH said:

I have heard a lot of people say it kills low RPM power because of the short runners.
what do think would result if you had a cnc aluminum 2" spacer made? would you gain more HP throughout a larger range, or is that just dumb?

I just like the price tag, would it be possible to run 2 of those 1" spacers on top of each other?,.....
im not thinking so

Click to expand...

You should be able to run two 1" spacers as long as you have the right length bolts and gaskets in between. But I'm not sure it would gain any more power.

But why spend $310 plus shipping on the comp when people have bought new Cobra intakes on Ebay for around $350 shipped?

Also even when you put the comp upper on its still on top of a lower that doesn't flow well.

I guess im just shying away from replacing the lower.
I just have that feeling that it will never go right and will leak, and ill have to do it 2 more times and post 4 threads on stangnet before i can drive the damn car again...
its always the way
so thats the only reason i guess.
plus I was always wondering about 2 spacers and 3 gaskets, this was my chance to throw it out there...

I first purchased my Comp Polymer upper when I still had the stock 302. Mods at the time were; Cobra Lwr, 24lb Inj, 70mm TB, 73mm C&L, and 1.7RR. I had 3.27 gears, and stock virgin heads. Before installing the comp cam intake I had the virgin Cobra upper in place, so I can provide a comparison between these 2 setups.

The comp cam upper did sacrifice some bottom end, until about 3,500rpm. Above 3,500 the car was much more powerful. Never had it dyno'd just SOTP. The bad part was the low end loss, which was almost unbearable. Getting moving from a stop was embarrassing. I was actually unhappy with the comp cam upper, until I put in the 351w.

With my current setup, the comp upper is ideal, as it allows the Lightning Lwr to breathe at full capacity.
I would not recommend using this intake with boost however. I have had some trouble getting it to seal, and have found that silicone is a must between the upper and lower half of the Comp intake. I think boost would just blow this thing apart. When I move up to boost on this car I will be swapping the Comp upper for a TrickFlow, or other Al upper.

My recommendations for using this intake are...
Pair it with a Cobra/GT-40 lower, which should flow a little better than stock.
Swap gears for 3.55 or bigger to help diminish the low end power loss.
Any change made to the heads and cam to improve airflow will greatly enhance the upper end gains.
These intakes are great for h/c/i strokers, whether 302 or Windsor based. The added flow of the Comp upper will come in handy with the extra cubic inches. The loss of low end with a stroker motor will not be as noticeable.

Also, plan ahead.
Don't buy an intake that you will outgrow fairly soon.

Hope this helps
jason

Just buy an explorer for around $200. And like mentioned above the Comp sucks with boost. Nothing but trouble.

I've always wondered why nobody made an aftermarket upper intake plenum to mate to the lower stock one. I replaced the lower intake gaskets on an 86 Bronco 302 EFI, and it was not fun. I was looking for a simple bolt-on upper that would allow the engine to breath all the way to 6k. I know the lower is restrictive, but the upper is just silly. The engineer who designed it should be slapped; tiny intake after EGR spacer, and rediculously long runners with a 90 degree bend.

When I saw the Comp intake in Jegs, I jumped on it, even tho $300 is steep. Then I checked out these forums and saw many replies that said low end torque would suffer. I put it on anyway, and I feel no loss of torque whatsoever. And it does have a good increase in horsepower from 4500-6000. I think the secret is that the stock lower intake and heads are small enough to preserve torque.

Plus, you have to consider that this intake is from Comp Cams, who have a reputation to protect. They supply Nextel Cup cars, for God's sake! I don't think they would market a POS that would leave 5.0 owners fuming.

mwm302 said:

I've always wondered why nobody made an aftermarket upper intake plenum to mate to the lower stock one. I replaced the lower intake gaskets on an 86 Bronco 302 EFI, and it was not fun. I was looking for a simple bolt-on upper that would allow the engine to breath all the way to 6k. I know the lower is restrictive, but the upper is just silly. The engineer who designed it should be slapped; tiny intake after EGR spacer, and rediculously long runners with a 90 degree bend.

When I saw the Comp intake in Jegs, I jumped on it, even tho $300 is steep. Then I checked out these forums and saw many replies that said low end torque would suffer. I put it on anyway, and I feel no loss of torque whatsoever. And it does have a good increase in horsepower from 4500-6000. I think the secret is that the stock lower intake and heads are small enough to preserve torque.

Plus, you have to consider that this intake is from Comp Cams, who have a reputation to protect. They supply Nextel Cup cars, for God's sake! I don't think they would market a POS that would leave 5.0 owners fuming.

Click to expand...

I appreciate you taking the time to post your experience.

Keep in mind that the Nextel cars are not using this intake, and if they did they have very little concern for low end.

If you put the car on the dyno, and compare the stock intake to the comp intake, you will see a loss in the low end. Maybe not much, but it will be there.
I am curious why you did not feel the loss as much as I did.
Some theories of mine on the matter...
1) You have taller gears than I did when I swapped to the Comp intake.
What gears are you running?
2) Your car is lighter than mine, as I have a LARGE soundsystem.
Both of these would make the loss of low end more dramatic.
3) You mated the Comp intake to the stock 302 lower, VS. me using a Cobra lower.

Interesting to note the differences.

Also, I used to curse automotive engineers, and their seemingly absurd designs. That changed once I started taking some classes in college that covered some of these issues. Once you crunch some numbers on how runner length will affect the power band, it becomes more clear. Also keep in mind that the Mustang was not designed to be a high revving car. The reliability of a motor starts to diminish with rpms over 5-6k, and most new car buyers (v8 purchasers anyway) are looking for more torque than hp. HP numbers look good on the brochure, but Torque is what sells cars.
Just some of my thoughts for the discussion.

jason

Yeah, I suppose with all the money Comp Cams makes on racing, maybe a little black mark in the aftermarket wouldn't concern them. What I find weird is stock cars are carburated, and have very high rise intakes (Tunnelport? Tunnelram?) Those intakes have long runners, and are good for high horsepower at 8k-9k rpms. But old carburated street cars have low rise, short runner intakes for more torque. Why is it the opposite?

I think the biggest difference with my car is the original lower intake. I'd love to get a Trick Flow or the new BBK dual plenum setup, but that will probably be in the far future. Too many projects around the house.

My rear end is 3.27 (originally 3.08, but had a little OOPS with a tall curb).

Original sound system, and nothing else that would add weight.

I think I do have some torque loss from 1k - 2k, but beyond that it pulls like a freight train. I really should have it dynoed, only way to know for sure.

One problem I did have at first was with the PCV. I had it going directly into the plenum, and it killed the vacuum. I did some hose swapping with the little plastic manifold, and took care of that.

Mike

mwm302 said:

........ I was looking for a simple bolt-on upper that would allow the engine to breath all the way to 6k. I know the lower is restrictive, but the upper is just silly. The engineer who designed it should be slapped; tiny intake after EGR spacer, and rediculously long runners with a 90 degree bend.

Click to expand...

Mike I'm with you. The stock upper is an absolute POS. It also restricts access and looks f***n ugly .

I don't know what the inside design the Comp unit is but back in 1999 I fabricated my own version of an upper and the bum dyno showed it worked much better than the stocker in all areas. It worked so well I looking at how to get it commercially made for sale . Later I fitted some GT40x alloy heads so I also fitted a GT40 lower and again made another alloy upper to suit the GT40 lower with the same success.

IMHO long runners suck so don't be afraid to experiment .

Currently I'm fabricating an 8 trumpet upper and lower. I done some test runs and it is awesome even with air/fuel ratio issues and a major PCV oil issue. I'm currently putting it back together and should finish tomorrow after having made some changes to resolve the PCV issue. I believe the oil was probably also responsible for the air/fuel issues.

mwm302 said:

One problem I did have at first was with the PCV. I had it going directly into the plenum, and it killed the vacuum. I did some hose swapping with the little plastic manifold, and took care of that.

Mike

Click to expand...

Mike,
Can you elaborate on the pcv issue?
Many people have issues with the pcv, no matter what intake they use
I may be able to offer some advice, as I have almost sorted out my issues
Maybe what you have tried will solve my issues

Ozrunner said:

Mike I'm with you. The stock upper is an absolute POS. It also restricts access and looks f***n ugly .

I don't know what the inside design the Comp unit is but back in 1999 I fabricated my own version of an upper and the bum dyno showed it worked much better than the stocker in all areas. It worked so well I looking at how to get it commercially made for sale . Later I fitted some GT40x alloy heads so I also fitted a GT40 lower and again made another alloy upper to suit the GT40 lower with the same success.

IMHO long runners suck so don't be afraid to experiment .

Currently I'm fabricating an 8 trumpet upper and lower. I done some test runs and it is awesome even with air/fuel ratio issues and a major PCV oil issue. I'm currently putting it back together and should finish tomorrow after having made some changes to resolve the PCV issue. I believe the oil was probably also responsible for the air/fuel issues.

Click to expand...

Can we get some more pics of that setup?
You can pm / email me if they are a pain to post.
I like the full trumpet ports
Did you have to fab those, or does someone supply them?


PCV oil can cause some issues with your mixture.
Also, keep in mind that O2 sensors will be destroyed by prolonged exposure to rich or oily mixtures.

Ozrunner - that.....is beautiful! You could win some nice trophies at car shows with that setup; a classic Weber look. BTW, I just figured out you're from Australia - I see the master cylinder on the right side of the car. You Aussies have some cars we would love in the States, especially Falcons.

vristang - As you probably know, the stock upper has a little vacuum "tree" underneath with 2 small and one large fittings, as well as a T fitting. I think the PCV went to the large one, or to the T fitting. The plastic box has three 1/4" NPT holes in it, so you have to get creative with the plumbing. I had both the supply line from the little vac manifold on the firewall and the PCV going to one hole with a T fitting. Took the car out, had no brake boost, and NO TORQUE! (How about that?!). I temporarily plugged the PCV hose and had tons of vacuum. I then took the hose that goes from the vac manifold to the 4 port round fitting on the passenger side and plugged it into the T fitting, and ran the PCV hose to the vac manifold. I also replaced the PCV valve with a shorter metal one from a 1970 Mustang, and it ran great (the original valve was quite old). I then bought the proper PCV valve, and now I'm experiencing some vac loss. I'll either go back to the '70 valve, or restrict the flow from the new one slightly. Maybe one of those disc shaped check valves in line with the PCV will do the trick. We shall see.