What To Expect From Comp Polymer Box Upper And Gt 40 To Switch To Holley Sytemax Or Tfs R Intake

[fiveohlover]

I have a 331 with afr 185 and comp xe 274hr cam and a ported gt 40 lower with comp polymer box upper 30lb injectors 76mm MAF. Had it dynod last year and made 345rwhp at 5900rpm and 347 rwt at 4200rpm. Tuner told me that he thought my intake was holding me back. Thinking of switching to a holley or a tfs r intake and curious what you guys think i could pick up by switching from the box upper and ported gt 40? Also from switching intakes will my power band change much? And will i have to get it tuned again?

 

[fiveohlover]

Found an thread off a google search and guy had almost same setup as me but had RPM2 instead of holley, car made 364 @ 5700 and 370rwtq at 4500
331 dyno results - Ford Mustang Forums
Basilio_Dyno.jpg Photo by smrtbeenr | Photobucket

 

[A5literMan]

The Holley and RPMII are very similar. I would expect that you would pick up an avg of 10-15hp and .2-.3 in ET.

 

[fiveohlover]

How about the r intake? Now just trying to figure out if its worth the time and money for the extra 15 or so...

 

[A5literMan]

The Holley and rpmII are better intakes. The TFS r is ok. It looses to much low rpm tq to justify maybe 5 extra hp over the systemax at high rpm. In the old magazine dyno shootout the R actually lost to the systemax if you took the avg power over the powerband. You'd run a quicker ET with the systemax.

If you're looking for maximum power and/or quickest ET, then you should swap out the intake imo. If you just like the appearance of a particular intake and have the funds I'd swap. Is it really worth it...that's probably a personal preference.

 

[7991LXnSHO]

The box/ported cobra has much shorter runners than the others. I would only run it with a high RPM motor, preferably with a supercharger. At least that is where I first saw them used successfully. Where do you want the power band? That will better answer which you need.

 

[90lxwhite]

Where do you want the power band? That will better answer which you need.

Took the words right out outta my fingers. @fiveohlover What do you use the car for? Cruising the streets in a mean fashion or are you trying to win a spot on Pinks All Out? Do you see 6k rpm very often? I mean you'd pick up that 15 or so at higher rpm's which is cool if you're trying to pick up a tenth or whatever in the 1/4. I guess it all boils down to if ya have the funds and are trying to shave a little time off at the track and or looking for dyno sheet bragging rights.

 

[fiveohlover]

I built the motor to be a more mid range and up with the power band, i have driven cars both with high hp at a higher rpm and cars that fall off at like 5500. I want the car to have a nasty midrange and to keep pullin but just want more power and feel that my motor has much more potential...car rarely sees the strip but i did once and my best time was 12.5 at 112 on street tires. But i just want to be able to beat 80% of the cars that i see running the streets

 

[A5literMan]

Add a Vortech. Seriously. An intake or other bolt on isn't going to make a huge difference. I do have a question about your present setup. You state 76mm MAF I assume that means you have a C&L? If so ditch it for a Pro-m. Also your combo is a little mild. For an example I'm expecting to see similar dyno numbers out of my stock shortblock 302 build. So if it were my car and I was looking for some descent power I'd add either a Vortech or nitrous. So many people are scared of nitrous. I've ran systems on many cars for many years. Never had a problem. If you just wanted that occasional "big kick in the pants" buy a good nitrous kit. Easily gain .7-1.5 sec in ET (depending on jetting and your set up). Can buy a kit for almost the same price as a new intake. Just a fwiw

 

[fiveohlover]

Add a Vortech. Seriously. An intake or other bolt on isn't going to make a huge difference. I do have a question about your present setup. You state 76mm MAF I assume that means you have a C&L? If so ditch it for a Pro-m. Also your combo is a little mild. For an example I'm expecting to see similar dyno numbers out of my stock shortblock 302 build. So if it were my car and I was looking for some descent power I'd add either a Vortech or nitrous. So many people are scared of nitrous. I've ran systems on many cars for many years. Never had a problem. If you just wanted that occasional "big kick in the pants" buy a good nitrous kit. Easily gain .7-1.5 sec in ET (depending on jetting and your set up). Can buy a kit for almost the same price as a new intake. Just a fwiw

You do have a point there. The problem with nitrous and cant use it all the time and refills would get spendy. Also i have been told to never spray with that polymer intake

 

[A5literMan]

Bottle refills do add up. I forgot about that intake.

 

[Boosted92LX]

I have the rpm II with 10 psi, and my rev limiter is set at at 6500. I hit it before my torque falls off. But then again, that's a turbo for you.

 

[fiveohlover]

Ya boost would be nice but not enough $$. Would it be worth it to possibly find a holley or rpm2 and get it ported? Just don't know if i want to swap an intake for only like 15 hp.

 

[90lxwhite]

Ya boost would be nice but not enough $$. Would it be worth it to possibly find a holley or rpm2 and get it ported? Just don't know if i want to swap an intake for only like 15 hp.

Depending on what kind of cars you're including in that 80 percentile that 15 hp might not get u there

 

[A5literMan]

The rpm or systemax will flow enough otb. Your power "problem" is more based on the h/c/i combo. If you're looking for say 50 more hp you'll have to address the entire combo of parts. Id get a better intake AND a better cam. The proper combo should/could get you very close to 375-400rwhp(depending on compression ratio,intake,cam,MAF,tb,headers,etc). The intake alone would pick up some power and my estimate could be a little low. It's possible you pick up more than 10-15 maybe closer to 20+. I'm not 100% sure on that upper intakes flow rate nor the port job on the lower. I know that there is a substantial difference between a stock gt40 intake and a Holley/RPMII. You can sell the current intake to mitigate some costs. You also can look for a used intake. These go for around 350$ on the corral all the time. You easily could end up only spending a couple hundred or less for a new set up. I feel it would be worth the experiment for more power. But that's just my opinion.

 

[fiveohlover]

Ya good thoughts A5literMan, I know my h/c/i combo isnt really crazy but i shure beats lots of people with 331 putting in alphabet cams in there cars. always heard good things about my comp xe274hr and have seen it make good numbers N/A. But an intake is definitely on my bucket list. Might save up a little more to get it ported also. Do you guys think i will need a new tune if i swap intakes? because thats at least another $350

 

[A5literMan]

I don't think an intake change alone would need a new tune. It wouldn't hurt to get one though. I'd swap and see how it felt first. The comp cam is a good ots cam. I just know that a custom could improve your numbers. Definetly not necessary unless looking for that last bit of performance.

 

[7991LXnSHO]

I think that box intake has such short runners (lower intake only) that you are going to be happier on the street with a more balanced performance intake. The cars that ran fastest with them spun the snot out of them and saw limited cruising time.
+1 on seeing how it runs before getting another tune.

 

[fiveohlover]

Ya was also curious if i would possibly pick up some low end torque this an intake swap. Because my 331 feels more like a 302 for low end torque.

 

[90lxwhite]

Ya good thoughts A5literMan, I know my h/c/i combo isnt really crazy but i shure beats lots of people with 331 putting in alphabet cams in there cars. always heard good things about my comp xe274hr and have seen it make good numbers N/A. But an intake is definitely on my bucket list. Might save up a little more to get it ported also. Do you guys think i will need a new tune if i swap intakes? because thats at least another $350

$350!? For a re-tune!? Sheesh what are they charging an hr? It shouldn't take too long to dial it in after just an intake swap. If you were to purchase a new intake (not a "new" used one) and get a tune you'd be at or a little over $1,000, expensive experiment my friend. What's the asking price for a used systemax? Around $400? Even then if you add your "at least $350" for the tune you'd be at $750.. If you didn't get the re-tune how would ya know if you're experiemt was a success or not? I guess you could use the butt meter but all of our cars "feel a little faster" for a little while after a mod. Ie: "more throttle response" and "it pulled harder between x rpm's." Hard data is always nice to see, especially if it's in the + column. On the street I think you'll run out of road before you can take advantage of that pontential 15 horse gain.
Are there any other areas of the car that could use some addressing with that $750?