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Author Topic:   Performance Upgrade Q's
GTRocks
Gearhead

Posts: 2289
From: Lusby, MD, USA
Registered: Jun 99

posted 05-18-2002 03:55 PM     Click Here to See the Profile for GTRocks   Click Here to Email GTRocks     Edit/Delete Message   Reply w/Quote
My '93 GT vert is bone stock at the moment with the exception of the missing air silencer. I am just starting to mod it. I have a few questions on my steps forward:

1. Throttle Bodies. What's the stock size...60mm? What are the pros/cons to the 65mm and 70mm sizes. Would I notice much difference with this mod alone? Would I also need to upgrade the fuel pump and/or injectors at the same time?

2. Headers. What are the pros/cons to the different header types. ie Shorties, equal length, long tube. Are there legalities to consider (MD)? Are H-pipes legal? X-pipes?

Thanks,

Dave

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'66 Coupe C code
'93 GT 'vert

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Stewart
Moderator

Posts: 9155
From: Monterey, CA Mustangsandmore Member #437
Registered: Apr 2000

posted 05-18-2002 05:17 PM     Click Here to See the Profile for Stewart   Click Here to Email Stewart     Edit/Delete Message   Reply w/Quote
60mm is stock size on your car. I've read articles where there was no difference in HP while on a dyno, on a mildly modified 5.0, where the only difference was going from a 65mm T/B to a 70mm T/B. That being said, I have a 65mm on my '90. While I have no proof (read, times or dyno numbers) to show any performance improvement, I like having the 65mm on there because when I finally get a decent intake and heads, the increased airflow will be utilized. I'll also be putting on a 76mm C&L mass airflow sensor and air inlet tube, which will really allow the air to be pulled in.

If you wanna just slap on a bigger T/B, you won't need to upgrade anything else in order for it to function properly. The stock fuel delivery system is fine, and the stock 19lb injectors will work well for a fairly modified 5.0 engine. It's not until you get a power adder or you have some serious horses that bigger injectors are recommended.

Just remember, any increase in T/B size, without any other corresponding modifications, will push your power band higher up in the RPM range.

For mild mods (no power adders) you won't need to mess with your injectors or fuel delivery system. But if you do decide to slap a blower on it, an upgraded fuel system is strongly recommended. The system (fuel pump, fuel regulator, size injectors, size T/B and mass air sensor) would depend on your intended application and power adder setup.

Long tube headers are the best for performance, but shorties work great too. As far as equal length versus unequal length, again, like the long tube versus the shorties, unless you need that extra few horses because its a strip car, the "regular" unequal length will work fine for your car.

Equal length headers are a pain to bolt onto an engine and you have to raise the engine on the drivers side to get long tubes bolted on.

Unless you really need the little edge one gets from long tubes and from equal length, and unless your modification application strongly recommends them, personally, I'd stick with unequal length shorties.

As for the legalities of emissions in your area, I have no idea. Mike (fishtail) would probably be able to answer that one for you.

I know here in California, offroad H & X pipe equipped cars won't pass smog. I have to put my stock h-pipe with 4 cats back on the 5.0 whenever its smog check time, which is every two years.

Oh yeah, long tubes aren't street legal in some states because they eliminate the forward most cats nearest the engine.

Stewart

[This message has been edited by Stewart (edited 05-18-2002).]

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wythors
Gearhead

Posts: 2693
From: The cold, gray Pacific Northwest
Registered: Sep 2000

posted 05-18-2002 07:40 PM     Click Here to See the Profile for wythors   Click Here to Email wythors     Edit/Delete Message   Reply w/Quote
Dave -

The first thing to upgrade on your ride is the exhaust: Your car comes with an H pipe from the factory. It has two fairly restrictive converters in each pipe (total of 4). You can get street legal, high flow H pipes for about $400 from several manufacturers. You can also get "off-road" H pipes for around $120. If you have any emissions standards to meet, they're not legal in your neighborhood. The good news is that they bolt on for easy changing. As far as headers go, I have FRPP unequal length shorties on my '93 and I love them. They were a breeze to install and I could really feel the difference when I put them on. I wouldn't even consider the equal length headers unless you really like to cuss and spend hours doing what ought to take half the time. Long tubes are only needed if you are going to really pump up the ponies with a major blower. Whatever headers you go with, get ones that have a one-piece flange. It's the only way to go. The throttle body and egr spacer (always replaced together) are usually the next step. For most naturally aspirated applications, 65mm or 70mm are preferred. The biggest bottleneck in your system, however, are the heads. You might want to consider saving your pennies (100,000 of them to be exact) and bolt on a set of aftermarket heads of your choice. That will really wake that horse up!

Good luck.

Dave

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GTRocks
Gearhead

Posts: 2289
From: Lusby, MD, USA
Registered: Jun 99

posted 05-19-2002 10:28 AM     Click Here to See the Profile for GTRocks   Click Here to Email GTRocks     Edit/Delete Message   Reply w/Quote
I had seen ads for both the 65mm and the 70mm, and wasn't really sure which I should be headed for. Since there's little difference in price, I was thinking of going straight to the 70mm. Is there a downside to having a 70mm when you really don't utilize its potential?

My guess is that I won't be replacing the heads for at least another 18 months, if I do it at all. I'm getting ready to redo the '66 (cosmetics mainly), so I'm allocating my funds for that project first. Once that's done, I'll re-evaluate my plans for the '93. I would imagine by then that I'll need a new top which may crimp the budget a bit. I may also be swooned into a new one if they catch my fancy. Right now, I prefer my '93's styling to anything that's come out since, but the extra horses would be fun! The car is my daily driver and I thoroughly enjoy it.

Anyway, I was thinking that I could probably swing a TB and/or exhaust in the meantime. Can you just put shorties on without modifing the rest of the exhaust, or do you need to do the whole thing? Recommendations?

We do have emissions testing here, but I don't think it's nearly as stringent as it is in CA.

Thanks for the input guys! Dave, it's great to hear from you, I thought you had fallen of the face of the earth!!

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'66 Coupe C code
'93 GT 'vert

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Stewart
Moderator

Posts: 9155
From: Monterey, CA Mustangsandmore Member #437
Registered: Apr 2000

posted 05-19-2002 11:07 AM     Click Here to See the Profile for Stewart   Click Here to Email Stewart     Edit/Delete Message   Reply w/Quote
The downside to having a 70mm? Not that I know of.

As for putting shorty headers on, it really is fairly easy. The only "problem" I had when modifying my exhaust involved a small tube on the passenger side that ran from the engine bay to the factory H-pipe. The offroad H-pipe I was planning on installing had a nipple on the same side so I could reattach the pipe, but I couldn't get the tube off of the factory pipe and wasn't sure if I should cut it. I tried calling Ian (Gearhead) and Dave (wythors) to ask them, but by the time Dave got back to me, I had already taken the plunge and cut the tube. Dave told me to get a short length of heat resistant tubing from a muffler shop and connect the cut end of the tube to the nipple on the offroad H. I think the muffler shop called it silicone tubing.

Anyway, like Dave said, the shorty headers are a breeze. You don't need to change anything else with your exhaust because your '93 already has factory headers, and the aftermarkets are a direct swap. Just make sure to recheck the bolts for tightness after you've heated them up a few times.

As for the new SN95's having more horses than the Fox Mustangs, that can be remedied easier and cheaper than buying a new SN95!

Heads, intake, cam, headers, exhaust, pullies, gears, a proper tune, and of course a power adder will all give you a much faster car than the new SN95's are stock, and it will cost you less!

The 5.0's have a ton of aftermarket go faster mods available for them! Dart even has a new Ford engine block, the Iron Eagle, that can be dropped into a Mustang. Heh heh heh...I'd love to have a 351 rumbling in my Silver Fox! Or maybe stroke my 302 to a 347 and have some fun!

Stewart

[This message has been edited by Stewart (edited 05-19-2002).]

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4Zsnow
Journeyman

Posts: 51
From: Western Washington, USA
Registered: May 2002

posted 05-21-2002 07:51 PM     Click Here to See the Profile for 4Zsnow     Edit/Delete Message   Reply w/Quote
Stewart, While you are on the subject. I just picked up a set of GT40X heads and some 1.7 roller rockers. I have some "run of the mill" mid lenght headman headers for it (made to fit a wide range of windsors). Question: with a custom ground cam for touque more-so than top end, would I be better off with a 65mm t-body and egr, as well as a bigger a/f sensor? My concern is making the intake route too big and loosing some bottom end. Also at what point would a GT intake be warranted.
Hope I haven't pi$$ed you guy off by butting in with these questions.

Thanks

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God Bless Big Oil

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wythors
Gearhead

Posts: 2693
From: The cold, gray Pacific Northwest
Registered: Sep 2000

posted 05-22-2002 10:01 PM     Click Here to See the Profile for wythors   Click Here to Email wythors     Edit/Delete Message   Reply w/Quote
If you upgrade your MAF sensor, you're going to need to upgrade your injectors accordingly. What you've got going is still pretty mild. I wouldn't be too concerned about your MAF yet.

Dave

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Stewart
Moderator

Posts: 9155
From: Monterey, CA Mustangsandmore Member #437
Registered: Apr 2000

posted 05-22-2002 10:14 PM     Click Here to See the Profile for Stewart   Click Here to Email Stewart     Edit/Delete Message   Reply w/Quote
Please help me clear up a few things...

I hate to assume, but I assume, judging by the part of your question regarding the "a/f sensor", that you have a 302 5L roller engine, correct?

I am far from the most knowledgeable guy regarding engines. That being said, please tell me what "mid length" headers are.

If it is a 5.0 Mustang roller engine that you have, then the stock cam already has great bottom end torque, but since you have a custom grind, I'd contact the company who made the cam and ask them for the most desireable combination it would work with.

As for when the GT40 intake would be warranted, I'd say at any time. The stock heads and intake are the most restrictive part of the engine, and replacing the stock intake with a GT40 is always an improvement, and moreso if the heads are upgraded. Just remember, if you change the intake but not the heads, the performance difference will not be as good as with aftermarket heads.

Stewart

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Stewart
Moderator

Posts: 9155
From: Monterey, CA Mustangsandmore Member #437
Registered: Apr 2000

posted 05-22-2002 10:20 PM     Click Here to See the Profile for Stewart   Click Here to Email Stewart     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by wythors:
If you upgrade your MAF sensor, you're going to need to upgrade your injectors accordingly.

Dave


Actually, you can upgrade the MAF sensor to a larger diameter and still keep the stock injectors. C&L and Pro M both have larger mass air sensors calibrated for 19lb injectors.

But Dave is correct, while it is a popular upgrade, you might want to concentrate on other upgrades first.

Stewart

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4Zsnow
Journeyman

Posts: 51
From: Western Washington, USA
Registered: May 2002

posted 05-22-2002 10:58 PM     Click Here to See the Profile for 4Zsnow     Edit/Delete Message   Reply w/Quote
You guys are great!
Stewart, don't be so modest!

Me thinks too much I figure....
I will just start out with a GT40 lower and a cobra upper (upper is easy to change to a GT40 later and dump the cobra on ebay). 65mm t-body, stock mafs and injectors. A good staring point, ya think? Then go from there.

Cam resurch is where I am getting the cam. (have not ordered yet)

To answer the question on the headers: I called them mid's cuz they are a little longer than shorties and not full length. They are off road units. They are made to fit comets, fairlanes, cyclones and so on. I will be having them fit with o2 holes and coated, along with the Y pipe.

It is a roller motor. Picking it up from machine shop next week. everything is new, save the crank (turned and polished) Lifters,push rods, rods, pistons (.030 over) roller timing set.

GT40X heads should be here next week as well.
Taking the heads down to 60cc's.

I will save further upgrades like A/F sensor for later, so I can see what each mod does.

I am much more educated now. Thanks fellas!

BTW Dave, you are in the NW? Do you have a favorite junkyard?

Lynn

[This message has been edited by 4Zsnow (edited 05-23-2002).]

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wythors
Gearhead

Posts: 2693
From: The cold, gray Pacific Northwest
Registered: Sep 2000

posted 05-23-2002 12:28 AM     Click Here to See the Profile for wythors   Click Here to Email wythors     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by 4Zsnow:
BTW Dave, you are in the NW? Do you have a favorite junkyard?

Lynn


Summit Racing Equipment.

Just kidding. I live in Edmonds. The only 'yard I've ever dealt with for anything related to my '93 is Wild West Mustang Ranch in Woodinville. A lot of people have said that their prices are high, but I got a coupe decklid for my 'vert for $50. Pretty reasonable I thought.

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4Zsnow
Journeyman

Posts: 51
From: Western Washington, USA
Registered: May 2002

posted 05-23-2002 09:05 AM     Click Here to See the Profile for 4Zsnow     Edit/Delete Message   Reply w/Quote
Thanks Dave. I am kinda new to the area (AK transplant) So this will help greatly.
I am staring to like Auburn. Not too far from SIR or is it Pacific Raceway? Kids love the grudge matches.....

take care

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