Extrude-honing 99+ intake & other bright ideas

[woody]

OK I have a 99+ 4.0L intake, to be used on a future stroker build. The engine will be normally aspirated and modest compression. In other words, pump gas, no 'race cam' nothing really exotic, with the intent of it to outlive me. I may go with roller rockers, and plan to polish the CC and head ports with a basic 'gasket matching' clean-up.

The inside of the plenum and runners is pretty rough... a good bit of casting flash and a generally coarse/ugly texture. Since the 4.0 is port-injected aka a "dry" manifold... I am thinking that having it extrude-honed to clean it up.

*extrude honing is a process where an abrasive goo is pumped through an object to smooth areas inaccessible by the grinding wand. Like any other material-removal process, the grit of the abrasive determines the final finish.*

Also the exterior of the manifold is pretty rough as well... would it be a waste of time to smooth it up & possibly get it coated with a ceramic (heat-resistant) coating aka "Jet Hot" etc... I'm not exactly sure of the details, but the plan is to have some sort of cold-air intake... so with that, I'd think that any little things done to keep the air cool(er) will help.

Do the cast "webs" (gussets) between the runners serve a critical purpose? Either for strength, heat shielding, or to keep leaked fuel from dumping on the header? If these are not critical to the structure, I'd like to get them gone. It would make less area to polish up, and make it look "different"

I have a bored HO TB, 62mm. I see that HESCO has a 68mmTB. Overlaying circles on a graph-pad, OEM 55mm is tiny, 62mm is getting there, and 68mm is big. The inlet into the plenum would need enlarged a bit to take advantage of the biggie-size TB.

I won't dare say money is no object... and like my boss always says: "Just go buy a GM Performance crate 350-383 and quit screwing around with a straight-six..." Say the extrude honing process costs $600, the big TB costs $400, and the coating costs $100... is this "smart" money or "dumb" money spent? I guess that's sort of a rhetorical question, since there is always the "Coulda had a V8" thought lurking in the shadows.

Damn Jeep things...

 

[wolfpackjeeper]

I would say dumb money for most of it. if you can jet-hot coat the manifold on the cheap then I would go for than. I do not think that the coarseness of the intake actually hurts you. And I also do not think that 68mm would be worth it either, probably will make throttle response way too sharp.

I put my throttlebody on a lathe at home and took the ring out of the bottom. No more. I smoothed it up with a few grades of sandpaper then some pieces of buffing pad till it was good and smooth, then called it a day.

I would spend the money on a quality 3angle valve job and more head work. Use it to get better bearings, have the con rods heat soaked, shot peaned, and destressed. Get forged pistons instead of cast. Get new LT1 injectors instead of used Fords. That extra $1100 could go to a piggyback computer system to better control fuel.

Lots of stuff I would go with first. But that is just me. I am sure some others will chime in with other suggestions.

 

[gradon]

I don't know if it's worth it, but it would be a pretty sweet intake. I've been intrigued with the Exho process since I saw their demo vette years ago. I would read up on experiences from it to see what was gained, just to get an idea.

 

[Dr. Dyno]

Say the extrude honing process costs $600, the big TB costs $400, and the coating costs $100... is this "smart" money or "dumb" money spent? I guess that's sort of a rhetorical question, since there is always the "Coulda had a V8" thought lurking in the shadows.

I'd say dumb money, and you definitely do NOT want to remove the gussets in between the manifold runners. They add strength and keep the header heat away from the injector rail.
A 68mm TB is way too big for a mild 4.6 stroker. I have a modified Mustang 65mm TB on mine and I feel even that's too big 'cause the throttle response is very sensitive. I'd say a 62mm TB is the right size so keep the intake manifold opening 62mm as well.
An extrude hone wouldn't be a bad idea but not for $600. Save that towards a Unichip piggyback computer especially if you have the OBD II engine management system ('96+).
Don't bother with the coating either. A heatshield fixed on the underside of the manifold will do the job very nicely at a fraction of $100. Here's mine:

http://www.angelfire.com/my/fan/manifold.html

 

[KMK172008]

the coating would look nice but I bet you wouldn't see much gain for that money. I think that the extrude hone would be a great idea. Put the money from that coating into the heads.

 

[igotanxj]

In my opinion its dumb money. If it were me i'd spend it on getting the head ported, and doing valvetrain upgrades like bigger valves and a 7 angle valve job. Heads are where power is made. Then I'd spend my money on roller rockers, and a decent sized cam. To be honest tho, you'll never reach the power and torque range of a 383 stroker without forced induction or nitrous, and if thats the power range you're looking for, I'd say just do a V8 swap. I don't know much about the swap, but I'd be willing to bet it wouldn't be cheap either being that youd have to upgrade the entire drivetrain.

 

[wolfpackjeeper]

In my opinion its dumb money. If it were me i'd spend it on getting the head ported, and doing valvetrain upgrades like bigger valves and a 7 angle valve job. Heads are where power is made. Then I'd spend my money on roller rockers, and a decent sized cam. To be honest tho, you'll never reach the power and torque range of a 383 stroker without forced induction or nitrous, and if thats the power range you're looking for, I'd say just do a V8 swap. I don't know much about the swap, but I'd be willing to bet it wouldn't be cheap either being that youd have to upgrade the entire drivetrain.

you could probably build a reliable turboed stroker with methanol or spray for much less than a 383 swap

 

[Dr. Dyno]

To be honest tho, you'll never reach the power and torque range of a 383 stroker without forced induction or nitrous.

Given that a 4.6 stroker only displaces 280ci, I don't know how anyone can even think that it would come close to a 383 SBC stroker in HP/TQ without forced induction.
If you want a 383 SBC level of HP/TQ from 280ci, make a close copy of my "poor man's" stroker using the 4.0 rods with KB944 pistons and add a mild 5.5/6.0psi of boost from a supercharger (choose from Kenne Bell, Avenger, Hesco).

I'd say just do a V8 swap. I don't know much about the swap, but I'd be willing to bet it wouldn't be cheap either being that youd have to upgrade the entire drivetrain.

Definitely not cheap and definitely not a stroll in the park either (many many man hours needed to complete it). Figure on it costing close to $10k with engine/tranny/axle/brake/suspension/chassis upgrades. If you have the mechanical knowledge, money, time, facilities, equipment, and an assistant to do the job, go for it. If you have to pay someone else to do it in their workshop, forget it.

 

[woody]

I guess that answers it IF I could get the honing done for less than I think, then it's a possibility. There's a place semi-local that does it so will check them out.

Good idea on the heat-shield... I have a roll of that stuff at work (1.5" wide for shielding fuel lines & wiring) Not "sexy" like a coating would be, but a fraction of the cost, and little time to install. I'll do more reseach on the pricing as well, but the matting is a lot of bang for buck.

Note that I am not intending to build a full-boogie race motor... just a mildly improved version of the 4.0L Renix ECU on HO head. (LOL I tossed in the 68mm TB/plenum inlet idea mostly as a BS checker... already have the 62mm TB in hand.) The intent is more torque from idle to 3500-4000. In all the years of 4-wheeling a 4.0l -and around others with same- I'd say that if the situation requires flattening the carpet much past 3500rpm sustained, you're pretty well fooked, and better off taking the hook before the junk starts flying.

IF I were to build something with a V8... it probably wouldn't be an XJ... too many things to do (each with potential for me to screw up)

OK a RELEVANT question! 99+ intake on a 91-95 head with port-matching... which intake/exhaust gasket is preffered, or does it matter? Seems like the newer ones are different than the older ones (more material IIRC)

 

[Boostwerks.com]

1. the rough casting is a good thing. It provides a buffer zone of air for the intake air to move on. I forget what this is called, but you definetly don't want polished intake runners.
2. the main benefit you would get from extrude honing would be the gained volume inside the manifold. Taking that into account, there are are some cheaper more effective options for you...

- don't worry about it, and just use what you have because the increase will be neglegible at best.
- Cut the center part out and build a sheet metal plenum at the center of the runners.

 

[wolfpackjeeper]

1. the rough casting is a good thing. It provides a buffer zone of air for the intake air to move on. I forget what this is called, but you definetly don't want polished intake runners. .

I believe it is called the boundary layer.

 

[alex22]

I've seen a set of cast iron exhaust manifolds that were extrude honed. They looked very nice and only took half the power away from the engine that stock manifold would have when compared to a nice header. They were not cheap and we only used them because the customer wanted his car to look stock. It definatly has its place but.... As everybody has said, you won't see the HP/dollar with the extrude honeing. There's a good writeup on Mallcrawlers about a 99+ swap and how he did it allong with numbers from a chassis dyno.

~Alex

 

[BBeach]

I believe it is called the boundary layer.

Yeah but it'd be there for the smooth one anyways. One thing the roughness will do though is cause more turbulence than if it was smooth. That being said it might mix the fuel a little better. Just a guess.

 

[Boostwerks.com]

Yeah but it'd be there for the smooth one anyways. One thing the roughness will do though is cause more turbulence than if it was smooth. That being said it might mix the fuel a little better. Just a guess.

Many well known head porters agree that a smooth intake runner surface will actually cause more turbulance than a rough consistant casting finish. This is the same concept as the dimples in a golf ball.

For shits, I've always wanted to paint a car in a hammered rustoleum and compare gas mileage results. But I honestly think the concept only starts to come into play when the air velocity reaches near "sound barrier" levels.

 

[alex22]

why just rustoleum. take an air powered paint scaler to the all the exposed sheet metal. I wouldn't worry about the boundary layer being effected as long as you have a coarser media pushed through the manifold.

~Alex

 

[yossarian19]

Uhm, is that a Fallout icon I spy?
On topic: I think the "dimpling" or regularized-turbulence effect only serves to break up the vacuum left behind a fast-traveling object / counteract the positive pressure zone built up on the front of a fast mover. You'd be talking much rougher than rustoleum on an object the size of an XJ, ans much faster than a 4.0 will push it. Or a Chevy 502 for that matter.

 

[ChevelleSSLS6]

the boundary layer effect works as follows... (edit: I think this is how it works)

a layer of air sits 'in' the dimples and such, and the air (in this case coming into the engine) has friction with this air, rather than the dimples and such. Air has less friction than smooth metal, and I'll assume less heat transfer as well.

 

[alex22]

Here is the link for the mallcrawlin writeup on the 99 intake http://www.mallcrawlin.com/forum/showthread.php?t=6355 someone PM'd me looking for it so I figured maybe there are others who might like to see it. The slight tumbeling air that attaches itsself to the port wall allows the main air stream to flow over it like the roller tracks of a factory.

and yes, it is a fallout 3 iccon release date: October 28th.

~Alex

 

[Talyn]

I got a quote on the extrude hone process from kennametal. $685. Too rich for my blood. I did a hand polish and port and port matched the intake and opened it up a bit. It definitely made a noticeable difference. I lost just a touch of low end torque, but after it passes 3000 RPM you can definitely feel a difference. I kept the stock valves and this head replaced a big valve head with no other work on it. I spent 60 hours on porting and polishing the head and intake manifold. Polished the chambers, polished the exhaust tract and stopped at 80 grit on the intake tracts. Stopped at 80 grit on the intake manifold and I blended it as far back as I could go, which was around 4 inches. Finished off with 32* back cut valves and a 3 angle valve job.

It ran great and had so much more top end. However, it only lasted 5 days as a Comp Cam lifter failed because they put it together wrong. Its now waiting for new parts and should be back on the road this weekend... again.

 

[ChevelleSSLS6]

I got a quote on the extrude hone process from kennametal. $685. Too rich for my blood. I did a hand polish and port and port matched the intake and opened it up a bit. It definitely made a noticeable difference. I lost just a touch of low end torque, but after it passes 3000 RPM you can definitely feel a difference. I kept the stock valves and this head replaced a big valve head with no other work on it. I spent 60 hours on porting and polishing the head and intake manifold. Polished the chambers, polished the exhaust tract and stopped at 80 grit on the intake tracts. Stopped at 80 grit on the intake manifold and I blended it as far back as I could go, which was around 4 inches. Finished off with 32* back cut valves and a 3 angle valve job.

It ran great and had so much more top end. However, it only lasted 5 days as a Comp Cam lifter failed because they put it together wrong. Its now waiting for new parts and should be back on the road this weekend... again.

:variety:which heads are the big valve heads? I'm told 91-95 HO heads, but I have a 96 HO... is there a difference in cylinder heads?:variety: