Mild Engine Build - Right Track?

This is a build question and an injector question. I had originally posted in OEM Tech, in the injector thread but maybe that's been so beat to death, no one is looking.
I know it's probably bad form to post in 2 places, so I'm asking for forgiveness ahead of time...

Anyway, 1992, 89,000 miles, 4.0/auto, stock gears,orig. size tires.
Looking for a little help. I've been reading about injectors and engine mods here and on Cherokee Forum until I really do think I'm blue in the face.

I'm restoring a 92' on a rotisserie and have the floor pans done, engine and trans out and painted.
This is more or less a stock build with Old man Emu 2" lift. No big tires.etc.

I'm an old guy, been there done that. I can look at plugs and rejet a carb, but this is my first time modifying a F.I. engine. I'm looking for maximum "driveability", with a low to mid-range hp increase.

My thoughts are:

1. Borla long tube headers, with 2.5" Cat., pipe, and muffler.

2. Port matching the head and manifold to the gasket.

3. Mopar purple camshaft, [Camshaft, Lifters, Hydraulic Flat Tappet, Advertised Duration 240/240, Lift .430/.430, Jeep, 4.0L, Kit] with lifters and springs.] 900-4800 rpm.

4. Modified stock airbox with highflow flat filter. [inlet to box extended to opening in rad.support].

5. 62mm throttle body

6. Neon 703 injectors on 99+ intake

7. High flow water pump.

Here are my questions;
Will the 703's flow enough for these modifications? I mostly see them recommended for stock engines.

Do I need to switch from 39lb FPR to the 49lb Regulator? Would this generate more flow from the 703's? Too much?

I was also going to install an adjustable MAP sensor for fine tuning the air/fuel mixture on the dyno.

Like I said, a mild build.
Am I on the right track here?
thanks,
robj

p.s. please, no stroker suggestions, I'm not interested in going that route.
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tricyclerob said:

2. Port matching the head and manifold to the gasket.

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No, don't gasket match anything. Match the manifold to the ports. Don't mess with the exhaust port except to clean up the casting.

4. Modified stock airbox with highflow flat filter. [inlet to box extended to opening in rad.support].

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I recommend using a large cone filter and making your own air box.

6. Neon 703 injectors on 99+ intake

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Stock injectors will support your mods just fine.

Do I need to switch from 39lb FPR to the 49lb Regulator? Would this generate more flow from the 703's? Too much?

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Don't mess with the FPR.

I was also going to install an adjustable MAP sensor for fine tuning the air/fuel mixture on the dyno.

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Keep in mind that it will change the AFR over the whole range in open loop.

Enlarging the throttle body and exhaust will slow the incoming and outgoing flow velocity, which hurts low/mid torque. Your list "may" add some measurable upper RPM hp but will almost surely hurt your low/mid range torque curve. It's easy to gain hp at one spot on the graph. Gaining hp and torque over the whole graph is the hard part. The factories have lots of engineers that would have built it like that if it was that easy. If you want the best power for daily driving and reliability, stick with stock components. Throwing components at these engines is like lip stick on a pig.

genevamotorsports said:

The factories have lots of engineers that would have built it like that if it was that easy.

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The factories have engineers that work toward emissions, low cost, longevity and NVH. Not max performance.

If you want the best power for daily driving and reliability, stick with stock components. Throwing components at these engines is like lip stick on a pig.

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Nothing he is proposing will hurt longevity and are proven to work.

genevamotorsports said:

Enlarging the throttle body and exhaust will slow the incoming and outgoing flow velocity, which hurts low/mid torque. Your list "may" add some measurable upper RPM hp but will almost surely hurt your low/mid range torque curve. It's easy to gain hp at one spot on the graph. Gaining hp and torque over the whole graph is the hard part. The factories have lots of engineers that would have built it like that if it was that easy. If you want the best power for daily driving and reliability, stick with stock components. Throwing components at these engines is like lip stick on a pig.

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Disagree. Do a residual vacuum test at WOT. If there is residual partial pressure you have a restriction. Changing to a 60mm throttle body along with a cat-back exhaust and cone air filter woke up my low-mid torque more than anything else. To mess with flow velocities that will impact exhaust scavenging you need to change the diameter of the tubing on the header.

Listen to Talyn. He knows what he's talking about and has the real-world testing to prove it.

What that guy said.

I like to think I know a thing or two but I always read talyns post twice.

I think what I proposed are pretty much standard "hot rodding" practice, without going overboard in any area.
Better flow in, better flow out, in balance, more hp pretty much across the range. If I get a 15-20hp increase, I'd be pleased as punch, 10-15 would be ok as well.

In most cars, one of the prime objectives of the airbox, in addition to someplace to hold the filter, is intake noise reduction. In some instances a cone has more intake noise and that 'feels' like more power.

I was the hot shit riding around in my father's '62, 327 Chevy with the air filter in the trunk. No more power but it sure sounded like it! [dang, hadn't thought about that in a looong time]

I'm not saying a cone won't help but I was going to try and modify the stock box first, with some internal smoothing and replacing the accordion section with smooth pipe. I like the idea of a ram effect with the oem intake tube of the box sticking through the radiator core support.
I looked at the surface area of the flat filter [which seems larger than the area of some [most?] cones and if replaced with a high flow filter may work well, and look stock. I think the plastic box would absorb less heat than a fabricated metal box, especially if lined with insulation.

It might be "fun" to dyno with a stock box, a slightly modified box, then a cone.

I was going to replace the stock injectors anyway and thought the 4 hole would aid in atomization. No?

Thanks for the tip on cleaning up the ports. Previously on SBC motors that I've done, I put a slight taper, starting back 1/2" to 3/4", just enough to match everything to the gasket. No?

I agree that manufacturers build to meet emissions and the demands of mass production. Otherwise every engine would be "blueprinted", not assembled with "average" parts that meet a wide tolerance.

If I do have the head off, just for fun, I'll probably cc the heads. Not terribly hard to do, just takes a little time.

Any other hints?
thanks,
robj

Lol 15hp.

We aren't on the same page... My jeep builds like 400..

If you have a very, very good exhaust shop they can probably build you a better flowing down pipe. I had two shops try & fail to get it to clear my front driveshaft, though, until I lifted the Jeep.

The rest... sounds good.
If you are going to pull the head anyway, consider a real port & polish + maybe raising compression ratio.

The Borla is a long tube header, doesn't really have a down pipe per se, the bottom pipe looks decent, smooth bends.

I had a little trouble finding one for a '92, the Borla site lists only 93 and up, as do most of the other sites.
I found it here;
http://www.autoanything.com/exhausts-mufflers/borla-exhaust-performance-headers
Must have been a left-over. I think the only difference is a flange for the cat, as opposed to a slip fit for 93 and up.

I thought about porting and polishing, but then I would want to go to big valves, then balancing, then a roller cam and then, and then...

I know myself, and I've been down that road before with other projects. I was trying to keep this simple and looking pretty stock.

My first Jeep project was in 1974, a balanced, blueprinted, 350 SBC in a 1951, M-38. That was exciting... But I was younger then.

robj

tricyclerob said:

I thought about porting and polishing, but then I would want to go to big valves, then balancing, then a roller cam and then, and then...

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Big valves will be shrouded by the combustion chamber hurting flow. They are also heavier. The only company that makes a "roller" cam is 505.. which is made on a flat tappet cam core. Plus their support sucks.

balanced, blueprinted,

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lol.. i love it when people throw around those two words.

tricyclerob said:

I'm not saying a cone won't help but I was going to try and modify the stock box first, with some internal smoothing and replacing the accordion section with smooth pipe. I like the idea of a ram effect with the oem intake tube of the box sticking through the radiator core support.

Click to expand...

Smooth pipe will help, but ram air is a myth at road speeds. Marketing gimmick.

I looked at the surface area of the flat filter [which seems larger than the area of some [most?] cones and if replaced with a high flow filter may work well, and look stock. I think the plastic box would absorb less heat than a fabricated metal box, especially if lined with insulation.

Click to expand...

Surface of a large cone is quite a bit larger. The air in the air box won't be spending enough time nor hanging around the walls enough to absorb enough heat.

It might be "fun" to dyno with a stock box, a slightly modified box, then a cone.

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that would be interesting

I was going to replace the stock injectors anyway and thought the 4 hole would aid in atomization. No?

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Stock injectors are fine and the multi hole injectors are overrated. If your stock injectors are dirty replace them, but they and the PCM have enough leeway to support the usual bolt ons.

Thanks for the tip on cleaning up the ports. Previously on SBC motors that I've done, I put a slight taper, starting back 1/2" to 3/4", just enough to match everything to the gasket. No?

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No. Gasket matching is a bad practice. The gaskets aren't that precise and are way to large and will hurt flow by leaving a larger area in the part that will result in a loss of velocity. Plus the exhaust side on the gasket is really large.... gasket matching needs to go the same way as the words "balanced & blueprinted".

Making modifications to the actual port shape without reviewing the work on a flow bench is like shooting in the dark. You don't know which direction you are going in nor do you know if you haven't actually hurt flow. Smoothing out casting lines and grain, leaving a desired finish (rough intake, polished exhaust, polished chamber), and port matching is pretty much the only thing you want to do without a flow bench. Too much room for error on major modifications.

Otherwise every engine would be "blueprinted",

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lol.. There is that word again. Right up there with Ram air.

To me balanced is, all the rods weigh the same, all the pistons weigh the same, and the assembly is balanced. "Blueprinted" is probably a misnomer as it implies more than it really is, mostly cc'ing the heads to get as close as possible that each cylinder have the same volume. Basically attempting to make each cylinder perform the same.
That and good assembly practice, making sure everything is as it should be. I think it makes an engine run smoother, more than generating big hp.

Anyway, you've probably made this process simpler;

Headers and T.B., check

Gasket matching at the manifold only.

Cone, after trying the stock airbox mods

Stock injectors will work [are the 4 hole detrimental? if I'm buying new, you still recommend stock?]

No FPR change

What do you think of the camshaft selection? It appeared to be one of the "mildest" grinds, affecting mostly low and midrange.

Thanks for your input,
robj

I'm not a fan of the mopar cam's. In theory better (they have wider lobes) but they don't in practice seem to hold up as well as the aftermarket cams and don't have the same performance.

I prefer Comp Cam's, but there are a lot of options.

Give Russ at Bishop-Buehl racing engines a call and talk cam's with him, he's pumping some very solid 4.0's and strokers out and keeps notes of feedback from each different cam that he has used. I'm sure he'd be happy to spend a few minutes talking cam's with you - but if you spend too much of his time be a good chap and buy the cam from him, he does offer competitive prices.

Russ Pottenger
Bishop-Buehl Racing Engines
531 N. Lyall Avenue
West Covina, California 91790
Work (626) 967-1000
Fax (626) 967-7836
Cell (626) 673-2203
Email [email protected]
__________________

I don't think the 4-hole are detrimental -so long as!- the flow rate is the nearly the same as stock for the given fuel rail pressure. I don't think Talyn is saying they are detrimental, just over-hyped as being a magical change in performance and fuel economy. Typical claimed magical improvements are from people that really just needed new clean injectors to replace old worn out ones. As low as the miles you state I think you'll be fine with what you have.

My $0.02 to add is to put in an ail/oil separator between the CCV and the intake. Removing vaporized oil from the incoming airflow results in added power. I've seen it and others have as well.

I have zero background in porting so I defer to others who know far more than I.

If I did my intake over I would probably put in a Spectre cone intake with their smooth fittings assembled to fit. They have a neat fitting on the filter to extend the center of the cone with a hose to another port, which I would run to an opening behind the headlight. Then it pulls some colder air from behind the headlight in addition to the surrounding hot air.

tricyclerob said:

"Blueprinted" is probably a misnomer as it implies more than it really is, mostly cc'ing the heads to get as close as possible that each cylinder have the same volume.

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Blueprinting is interpreted as different things by different shops. Most just call it checking clearances and making sure they are in factory specs, which needs to be done on any engine. That wouldn't be considered blueprinting. I've seen machine shops use plastic gauge and call it blueprinting. Nope. True blueprinting is measuring everything and making sure it is with in factory spec. That would include items such as lifter bore alignment, lifter bore placement, cam bore and crank bore alignment and sizing, valve placement, deck height and clearance, volumes, bolt hole alignment, bore distortion, etc. Also, keep in mind that the factory specs (blueprints) have ranges as well so its not really making sure everything is an exact & precise number. If the engine received a real blueprint operation the bill would show it. That term is right up there with "ram air", "race cam" (3/4, 1/4, etc), and "cold air intake" in terms of marketing.

Gasket matching at the manifold only.

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Don't use the gasket to match anything. On the intake side you want the intake manifold runners to match the head intake port or slightly smaller. Never larger at any point as that will create a wall for the air to run into. As far as removing casting grain and lines that is fine, but don't polish the intake. Feel free to polish the combustion chambers and exhaust ports.

cal said:

I prefer Comp Cam's, but there are a lot of options.

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I'm not fond of Comp. Their cam grinds for our engines haven't changed for over a decade (there is a lot more to lobe design besides lift and duration), they still don't offer a kit that includes a spring that will fit the 4.0L, and you can call their tech support and get a different person each time with a different answer. They also don't like talking custom cams for our engines. They aren't bad cams, but to me they are the Walmart of cam companies.

SolarBell said:

I don't think Talyn is saying they are detrimental, just over-hyped as being a magical change in performance and fuel economy. Typical claimed magical improvements are from people that really just needed new clean injectors to replace old worn out ones. As low as the miles you state I think you'll be fine with what you have.

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That pretty much sums it up. I'm also thinking that there may be a reason Jeep never went with multihole injectors in the 4.0L even when they changed injectors and fuel pressure in the last years. They could have easily pulled a multihole injector out of their parts bin and used that.

My $0.02 to add is to put in an ail/oil separator between the CCV and the intake. Removing vaporized oil from the incoming airflow results in added power. I've seen it and others have as well.

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That is a good recommendation. I use a modified cheap ebay one on my stroker and a custom one on the 5.2L ZJ. Moroso also offers a very nice one as do other companies, but they are pricy. What you don't want is just an open canister (no baffles, no dividers, no mesh, etc.), which is what most of the ebay ones are.

Talyn said:

I'm not fond of Comp. Their cam grinds for our engines haven't changed for over a decade (there is a lot more to lobe design besides lift and duration), they still don't offer a kit that includes a spring that will fit the 4.0L, and you can call their tech support and get a different person each time with a different answer. They also don't like talking custom cams for our engines. They aren't bad cams, but to me they are the Walmart of cam companies.

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They build custom cams for our engines all day long, and have no problem talking about it.

And you're right, they don't offer springs for our motors.. anyone who's spending the time to change cams should be converting to a GM style beehive spring anyways, but thats an entire different conversation..

Last time I wanted to talk custom cams all they wanted to do was sell me an off the shelf grind.

Maybe its just a lack of being familiar with you? Russ has a series of custom comp cam's he uses in his strokers, but he's been working with them for a long time and is on a first name basis with his rep.

Sounds like the best way to go is just talk to russ and get one from him that he recomends.