inj housing porting without headers

[mike100]

Is there anything to be gained by induction improvements while retaining the factory exhaust manifolds?

The logical mod progression is to do the chip/exhaust, headers/ intake porting, followed by head/cam/ displacement increases. I can't do that as easily in CA- not because of getting caught, but because of switching parts back every two years.

I have a B&B catback, but I'm looking to tone that down as well if I can find a set of factory pipes to purchase/modify. May just have a custom 2.5" with a resonator made if it can be done cheaper than a Corsa... I feel that some more midrange punch could be gained by ditching the 3" x-pipe drone special this car has.


somewhat related: I actually don't know if my prom cal is stock either, but it revs to 7400 (indicated) and the skip-shift is not functional.

[LGAFF]

Yes, I did porting for a car and it gained 25rwhp, with stock manifolds

[sammy]

you can pop the prom out easy enough and see if its got a aftermarket tuner tag on it .you might have a tuner prom .you are right about the exhaust 3in loses low end unless you have a fully ported motor with headers . i have a ton of extra exhaust systems flowmaster cat back, corsa cat back, borla mufflers only, a 90 stk exhaust and a 91 stk exhaust pm me if you might be interested in anything above . rick hipsher ported his top end inj and plenum ,i believe he made 20+ rwhp with stk exhaust and no dyno tuning . maybe some of the calif. guys with headers will chime in on how they keep them .

[sammy]

when i was in ca i live in inyo county, the only county in ca that doesnt have to do smog testing .

[GOLDCYLON]

Yes porting will improve performance. Next logical progression is long tube headers. It a no brainer while you are there already mod and does not affect the car to detract visually in any other way. It is an unseen mod with the exception of increased performance.

[mike100]

you can pop the prom out easy enough and see if its got a aftermarket tuner tag on it .you might have a tuner prom .you are right about the exhaust 3in loses low end unless you have a fully ported motor with headers . i have a ton of extra exhaust systems flowmaster cat back, corsa cat back, borla mufflers only, a 90 stk exhaust and a 91 stk exhaust pm me if you might be interested in anything above . rick hipsher ported his top end inj and plenum ,i believe he made 20+ rwhp with stk exhaust and no dyno tuning . maybe some of the calif. guys with headers will chime in on how they keep them .

factory tag (the second calibration listed for '91- I forget the exact one, but it has an 'X' in it). I definitely want to talk about pipes. I understand the early resonator is restrictive though. From my previous experience with C4 resonance, only the stock muffler and somewhat with a generic turbo muff, are going to have minimal drone.

[mike100]

Yes porting will improve performance. Next logical progression is long tube headers. It a no brainer while you are there already mod and does not affect the car to detract visually in any other way. It is an unseen mod with the exception of increased performance.

If I have to get back into it for anything else, I want to be prepared to do what I want, budget depending. It sounds like a vicious cycle- may as well do wires, but then you should get new coils too, and if you got injectors, may as well pull the housings off to get them worked- hehe...It's not too hard to remove the plenum.

I'd be happy with late model LT5 power with a smart combination of things plus the chip.

[Locobob]

Here is a 91 I did a mild port on, before and after. No headers, no tune, just cat back.

http://www.pnwzr1.net/Robert/Misc%20Pics/Be-Afportingresz.jpg

[Aurora40]

Does the skip-shift light still come on? If so, it's probably unplugged vs a chip. Tach is hard to say, because so many are not accurate.

And yes, porting with stock manifolds is worth it. I did headers last. Headers have the most downsides in terms of a louder, rattlier car, and of course it's harder to pass a smog test.

[GOLDCYLON]

I did headers last. Headers have the most downsides in terms of a louder, rattlier car, and of course it's harder to pass a smog test.


100% correct even with Hi-Flow cats.

[LGAFF]

If I have time, might be pulling my intake off this weekend and selling on an exchange basis.....$450 plus your IH/Plenum and or $700 if I move it to 36mm port.

They are currently 36mm tapering to 34mm on the primary..all inj bosses removed, etc..

Going Siamese on the new motor

[mike100]

Does the skip-shift light still come on? ...


I have yet to see it- my 95 lt1 still lit up, saw it all the time- it was disabled somehow too. To be honest, I haven't put a lot of miles on the car yet, but I drove it 40 miles yesterday and didn't notice it.

There is no label on the prom- do people ever burn over the eeproms and not label them? I'll find out sooner or later.

[mike100]

If I have time, might be pulling my intake off this weekend and selling on an exchange basis.....$450 plus your IH/Plenum and or $700 if I move it to 36mm port.

They are currently 36mm tapering to 34mm on the primary..all inj bosses removed, etc..

Going Siamese on the new motor

I'm kind of tapped out on the purchase plus a couple of projects/repairs on it that I already started. Maybe in about 6 months....

thanks anyways.

[mike100]

Here is a 91 I did a mild port on, before and after. No headers, no tune, just cat back.

http://www.pnwzr1.net/Robert/Misc%20Pics/Be-Afportingresz.jpg

that is encouraging- no loss at the lower end at all.

[Paul Workman]

This is my story, and I'm sticking toit!;)

First, I didn't dyno my car after doing the top end P&P, before adding the headers and X pipe, etc, so I can lie like a rug about how great it was!:dancing

I went with Pete's proven model for the P&P; lets just say a 36 mm ball rattles through the plenum primary side like a BB in a down spout! And, the IHs discharged into the heads which had "a little" over 36.5mm openings at the top, and tapered along the entire length to a point just short of the valve guide bosses (approx 32.5mm stock 90s).

I was expecting about 25-30 hp (with a Haibeck chip installed & fueling setup for an additional 50 hp). However, I was flat amazed!! - I'd have to say it was ALL of 30 and felt closer to 40ish! My shift point moved up at least 500 rpm, and it showed signs of things to come when it was very hard to make it stick in first gear on asphalt. In other words, I feel I gained torque in the low/mid range if anything - certainly lost nothing that I could feel.

Next step was to install the SW headers, the SW X pipe, and remove the resonator (leaving the muffs alone). Frankly, I was hoping for the same magnitude of increase in performance that I got with the top end P&P, but it was not to be. I would guess I got about 1/2 the increase in seat of the pants that I got with the top end porting. I was a little disappointed, frankly. However, that was when I discovered a leaking exhaust valve on #8, which no doubt played a role.

Well, the next "holy cow!!!" had to wait until the head porting was done and Pete and Marc did their magic. Just one problem with it tho...I'm definitely needing some DRs, cuz the GY F1-D3s are no match for the RWTQ, and that is with stock 3.45 rear.

My recommendation is to go whole hog on the plenum and IHs and port match the heads for now. Then move onto the rest of it in phases as $$ allows.

Just a thought.

P.

[Pete]

I'm hogging out my extra set of heads as we speak,they are sold.

If any of you boys wanna see how the big dogs do it come on over.

Pete

[sammy]

i would dearly love to but the 2000 mile door to door especially with your guys white stuff makes it just a little tough . one of these days i will get my world in order so i can come visit and maybe leave that spare motor i have for you to do your magic on . till then i can only dream about all the fun you guys have . fbi is an awsome group.:cheers:

[FU]

I'd like to "blink" my self over there too Pete. Problem is that kind of science hasn't been proven. And I'd hate to leave some of my best parts in different Cities.

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Mike , I said it many times before and here it go's again. Nothing runs as sweet as a well done top end engine, period. Do the plenum ,I/H and heads if you can afford it.
Bet is that a nice intake cam will fly right past the CA. sniffers if needed. Maybe even a small exhaust cam with the right timing . If you want to get that involved.

There was some one in the club that used to hog out the stock headers/exhaust and leave the cat's working. I some what remember him being from the Virginia area.

Best of luck.

[XfireZ51]

The first year I got my Aqua car, I did a 36+ mm top end,
no headers. Car went from 110mph trap to 114.
Next I got a set of 1 7/8" Watson's with a MagnaFlow CatBack.
Car trapped 118.6 on street tires. Same motor is now in my
Black Rose car but w GVD ported heads and Pete's Stage 1 intake cam.
Hope to get car to dyno for tune before BG and see what happens.
The last dyno tune I did on top end and headers made 399rwhp.
BTW, tuning is a MUST if u are going to get the most out of nearly any mod you do,
IMHO.