Intake - To Gut or Not Gut, that is the question

[SVOJames]

I need some feedback here....

I emailed Bob at bobs log about doing me a ported, but not gutted, upper, along with a ported lower. He is willing to do this, but claims that from what he has seen personally, and what other customers tell him, I should go with the gutted upper.

I was talking with Jim at Motion Dynamics, while they were dyno'ing the car after putting on the ported big-valve head, and he said I should just go ported, not gutted.

I've got the 3 inch DP, 3 inch cat to dual 2.5's, T3/T4 hyrbid, ported E6, ported FMS big valve head, K&N cone in the fender, Spearco FMIC.

Seems to me that gutting the upper will give me shorter intake tubes, and will move the HP up to a higher range, while taking away some of the low end grunt.

What are your experiences?

James

[schlot]

You're right, by removing the interior material and using the later style manifold, it will move up the hp into higher rpms and reduce low end torque...or tork for you Canadians out there.

Maybe you could try the porting first and see if you like it. I'll sell you an extra set of '86 manifolds and you can gut them and then compare. Have a great day, eh!

[tateg]

I think you need to re-evaluate. Determine what your goals are and use the manifold that flows properly for those goals. Don't forget, your cam, head and intake should all match. You didn't post anything about your cam. I will do you little good if you are running a range cam and bolt on a set of gutted intakes.

FWIW I was running a gutted upper and ported lower on a VAM with no driveability or mileage issues. I was even running the stock injectors. I'm currently running a ported set. Down low I can't *feel* anything different(maybe the dyno could though). Before I swapped over to MS and 550cc injectors I felt like I was running out of steam at higher RPMs (before the gutted one did). But I made too many changes with the intake swap for it to be a fair comparison.


EDIT:
forgot to add. I've had this conversation with Bob. He says that the dyno has shown that the gutted intake makes more power up high but about the same torque at about the same RPMs as the ported intake.

[SVOinDC]

Ditto to tateg's comments. Bob has my upper in his que. I too had the exact conversation with him and was told his dyno showed no loss at the bottom and increase at the upper limits.

Jim at Motion suggests, however, that gutting is not the way to go. It all comes down to whom you listen to and what your end game is. I plan to run the car on track days more than auto X, so I am leaning more towards top end gains.

Mine will be gutted, it will be hard to quantify the results of just this as it will be going on with the knife edged lower, ported E6, Kirban and possibly bigger injectors.

Good luck-

[Henson]

Gut is not the word that should be used. Can you make it better? Sure. All depends what you want. You got a 2.3? 2.5? 3.0? What is the designed RPM? All intakes now a days are done on a computer and are run for several days, dyno tested, ran again on the computer, tested again and so on. Did they do this in the 70’s, probably but Not done too well. They relied on the Dyno more back then. Did our 4 banger get good dyno time? Well… Probably not.

To do this correct you need to have someone at Ford run a simulation for you. Hmm.

FYI- for stock conditions just smooth the castings out. You’ll be better off.

[TheViking]

I have Bob's gutted/ported intake on my 2.5 w/the Racer Walsh street cam setup. I've had the intake lying around for a couple of years so decided to try it out on the stroker motor. I don't have any drivablility issues that aren't typical on an SVO and I was getting 28 MPG to and from the reunion. It made 322 rwtq (3800 rpm, 17 lbs boost) at the reunion so I wouldn't say it killed the bottom end either.

Mike, maybe you can elaborate on your concerns. Meanwhere maybe Henson can get us some time on Ford's simulation computers when he's not corner working

[thomp22]

This topic has been batted around alot, so I figured I would give it a try. I guess I will see come reunion dyno time. I installed a gutted upper and knifed lower with a 60mm throttle body with adapter plate recently. I had a few other mods planned, but I think I will still put in a 255FP and leave everything else alone just to see. So I should be able to compare it to last years run. Of course weather conditions may be different. Haven't had any seat time yet to notice a change. I have the bumper cover removed to sand an repaint, hopefully soon. It seems the idle and and throttle response when revving are good. I guess I'll see, still have the stock stuff if it doesn't show any gain. No big deal changing it back, besides it gave me a reason to spend sometime on the SVO. Get alittle closer to her. My .02..

[TheViking]

That's why I wanted you to explain further. I just not smart enough to understand these things.

You never did 'splain the "serious damage to the driveability and fuel consumption values" though.

[under pressure]

Yeah what he said!

[SVOJames]

The car has the A-237 Roller cam (or whichever came with the FMS big valve head). It's a street car, stock electronics (which might get some tuneing) and the ultimate goal is in the 250 - 270 HP range, and reliable because it's seeing a lot more miles than I had planned.

I guess I was bothered because Bob told me to get the gutted intake without knowing anything more than I wanted the tall style to put on my 86 SVO. Jim knows much more about the engine, so I believe I'll take his (and Mr. F's) opinion. Heck, I ought to get two sets ported, and someone at the reunion can gut the second one, and we can do a straight dyno comparision, and possibly some seat of the pants testing.

I suffered some driveablity issues going to the big valve head over the stock head with the ranger roller cam. I no longer have the confidence to pass someone quickly at 60 mph in fifth, I now feel the need to downshift. I don't want to loose much more under 3K power.

James

[boostedbruiser]

OK here's my 2 cents from what i experienced...... I ran for the longest time a Fully ported Upper/lower non gutted......... I made good power with this intake for sure. I also talked with jim and yes his idea is you lose power down low, too much to be worth while on a DD car.

Now i really wanted to dyno the intake swap, since i later went with a gutted upper/ported lower, but i never got around to dynoing the car since i did a few changes at once. I will say that after doing the gutted intake and some exhaust work the bottom end didn't feel any better or worse, but the high rpms SEEM to pull better. also gained about 1 mph through the traps in the 1/8th but who knows if the intake did more change or my exhaust work.

I doubt i lost anything down low, but i honestly felt i did gain up top. ALL THIS TESTING WAS DONE WITH A A237 CAM.......... I say if you plan on more power in the future GUT IT.

Want more power down low???

Get a Boport 1.1 CAM. SAME characteristics of a RR (comes in early, like peak trq at 3700 rpm) without dying on the top end. And it makes more power all around...off turbo, on turbo... everywhere. My A237 cam peaked @ 4300 rpm and was a slugg under 3500 rpm. i truely hated it.

For the record the Essy 2277 cam is bad boy.... i made the most trq ever when compared to a boport cam, BUT one ittsy bittsy problem..... IMO it acts like a light switch. With the essy cam it was extremely easy to send the tires up in smoke.... even in 3rd just rolling into it. all of bo's cams were alot softer coming in (made a for a better DD Cam IMO) but still had the ooommmph up top when you needed it.

[boostedbruiser]

+1 vote.........Gut the upper, a proper cam later down the road will give you that low end grunt you want and will straight outperform the A237.
in fact sell the A237 for 200ish and then add 150... and there you go, boport cam ready to rock.
I PROMSIE YOU'LL LOVE THE CHANGE AND WONDER WHY YOU DIDN"T DO IT EARLIER....

[SVOJames]

Booster offers some interesting data, if only his location didn't show him from being what I consider a drug dealing area/country.

If only his profile showed him being from some place cool, like Plano, TX.

James

[boostedbruiser]

Booster offers some interesting data, if only his location didn't show him from being what I consider a drug dealing area/country.

If only his profile showed him being from some place cool, like Plano, TX.

James

If your trying to imply that i need to update my Location with the correct info.......... It is correct, i just moved. For about a year i'll be here. It gives me PLENTY of time to save money and build the ultimate shortblock for me..... get the auto working, stall, rearend, sway bar, turbo, new intake, new header, etc etc...................

[SVOJames]

Boosted,

Yes, I was implying you should update your info, but it seem I was wrong. I apologize.

James