Making a whole new intake

[1bad383]

I am sick of looking at the stock excuse for an intake on my 94' with the new Avant 6.2 conversion motor. I have the abilty to make anything I need, but would like to know from people that have done it / seen it done. I am thinking no intercooler (yet) going right from the turbo to the intake. Seems straight forward, but there are sensors and the CDR return to think about. Make a plate for the intake side weld a 2.5" elbow connected to some tubing to the turbo. Easy enough, I think. On the inlet of the turbo, not much room there. Thinking about doing a very tight 90* to position the filter at or near the stock fender inlet.

Does the stock intake do a good enough job to make all of this unnecessary? GM had to be on to something about the intake design, or maybe not. GM does some wierd stuff sometimes! I searched the Forums, found some pictures but just curious to get some feedback on what you guys and gals think.

[DA BIG ONE]

The diesel has no throttle plate so custom design is pretty much useless, the can run w/o intake manifold. Mods for gas intake manifolds are pretty much useless on a diesel.

Perhaps, match porting will yield some benefit but thinking not much to be worth porting at stock boost levels.

Going w/larger more efficient turbo porting and matching will help at upper rpms.

[More Power]

http://i189.photobucket.com/albums/z8/cheapracer/duramax_manifold.jpg

Something like this would look cool on either a 6.2 or 6.5, whether TD or NA.... ;)

Jim

[DA BIG ONE]

Jim, what do those manifolds bolt up to?

9 Runners on each one?

[DmaxMaverick]

Duramax. There are 8 runners, each. The Duramax has 2 intake valves per cylinder, each with its own port.

[1bad383]

After further review I can see how my orginal post was misleading as to what I intend to do. I do not want a sheetmetal intake, just a new top plenum to replace the portion where the 2.5" pressure tube connects to the intake, leaving the bottom half connected to the heads. It is a mostly stock engine nothing to set the world on fire. But just looking at the top half of the intake, it looks like one heck of a restriction.
Just trying to get the air comming from the stock -4 turbo in the best I can. Was even thinking of not going with an I/C, just running an intake tube on the driver side, down by the bumper then over to the inlet of the turbo. Using the passing air and the tube for a heat sink of sorts.

I have my race car to really get crazy with. And I do!! My friends give me crap about my theory of Overkill Engineering, no kill like overkill!

[DmaxMaverick]

Well. If that's all. Peninsular has an upper intake replacement that's nothing more than a plate with a 90° elbow welded to it. Simple, and no restrictions. You could fab something like that yourself, or purchase one from Peninsular.

[1bad383]

Right I was going to make my own, just curious as any gains by going to that style intake and any possible downfalls or things to avoid in making my own.

[DmaxMaverick]

No gains to be had at normal - moderate power levels. The only downside would be your time/materials, and perhaps fitment issues. At the very worst, it would be a benign mod. Cool, though.

[DA BIG ONE]

Jim, what do those manifolds bolt up to?

9 Runners on each one?

Can't understand how I came up w/9 runners, guessing some timers here.

[1bad383]

Well shoot, if there are only very small gains to be made stock piece it is! Now, what about an air filter set up? I'm in the mood to fab something up, don't want to waste the mood cuz I don't know when it may strike again!!!

[DennisG01]

Here's as easy thing. Don't know if it helps, but I don't think it can hurt. Actually, I haven't even driven the truck with this particular mod yet, as I don't have the new engine it, yet. In our trucks, the air comes in around the passenger side parking lamp assembly. This mod can be done using a Dremel tool and without removing the grill or lamp assembly. I had the grill off for other reasons.

http://www.thedieselpageforums.com/photopost/data/519/Air_Intake_Opening_-_Small.JPG

http://www.thedieselpageforums.com/photopost/data/519/Grill_Opening_-_Before_-_Small.JPG


http://www.thedieselpageforums.com/photopost/data/519/Grill_Opening_-_After_-_small.JPG


Sometime I will build a box, but in all the testing I did - when I had a working engine;) - (similar to TDP "Pull-Off" testing) I did not find a measurable difference by not having the filter boxed.
http://www.thedieselpageforums.com/photopost/data/519/Air_Intake_a.JPG

[1bad383]

What type materal did you use for your intake tubing? I was going to use a bunch of mandrel 3" exhaust tubing, but yours looks easier!

[DennisG01]

I used aluminum. I bought the aluminum and the rubber from www.intakehoses.com. It was pretty inexpensive. I originally used PVC, but found that underhood temps can soften the PVC to the point where I could squeeze the PVC and it would start to deform. Not alot, but enough that I wasn't comfortable with it.

[Hubert]

Small gain but maybe better even flow with new top. Not sure if its worth fabbing up lower half. I like the hummer plenum top half better the one Penisular sells. Or some other cobra head style that helps direct air evenly down the plenum and runners.

I remember some discussion a long time ago that maybe? the air rushes in the OE truck top intake half and bounces off the backwall of the lower intake and gets more air to the front cylinders and that is why the back cylinders have more heat problems when running hard ?????

[67_C-30]

I was faced with same dilemma for my turbo'd 6.2. I actually have a 6.5TD intake, but it looks restrictive, and I planned on running an I/C. I knew the Banks sidewinder run pressure chamber on a n/A intake, so I decided to use the dual plane CUCV intake and build a custom piece for it, so I could index however I needed to run my I/C hoses when I get to that point. I used a '70 Porsche oil bath air cleaner that I cut the bottom part off of and and welded a 1" spacer and the bottom off of a factory 6.2 N/A air cleaner. I put a thread insert the part that originally was for a vacuum line to plumb in my boost gauge. It looks pretty cool and and kind fits with the old school theme of my old truck.

I have thought about it some, and I originally wondered if the dual plane design has the same effect on a diesel as it does gasser. I don't think it will because the dual plane design with fuel and air going into the runners creates turbulance which in turn creates more low end torque. The exact opposite reason why single planes are high RPM engines is because they do not create as much turbulance. The dual plane does look better IMO, so that is worth at least as much horsepower as an Edelbrock sticker I would think!;)


http://i226.photobucket.com/albums/dd85/67_C-30/Pictures601.jpg

http://i226.photobucket.com/albums/dd85/67_C-30/Pictures602.jpg

http://i226.photobucket.com/albums/dd85/67_C-30/PRESSURECHAMBER.jpg

http://i226.photobucket.com/albums/dd85/67_C-30/PRESSURECHAMBER2.jpg

[EWC]

When I had my heads ported , we flowed the single and dual planes . Single was worth 20 more CFM than the single .

[67_C-30]

Single was worth 20 more CFM than the single .

Do you mean the single was 20 more than the dual?

[EWC]

Yep , it was like 178 for the dual and 197 for the single . Guess which one is going on my 6.2 Banks !

[67_C-30]

Good to know! Thanks for the info.

[DP]

There are some things that won't jive between gas and diesel engines, but intake and exhaust tuning concerning port volumes and volumetric efficiency will still apply. It's a little harder to think about the lower RPM ranges but the rules are still there. Have a look at these pics:

http://www.seriouswheels.com/2007/2007-Peugeot-908-V12-HDI-Engine-Side-1280x960.htm

http://en.wikipedia.org/wiki/Image:PeugeotV12HDiFAP_3.JPG

http://www.seriouswheels.com/pics-2008/a/2008-Audi-R10-TDI-Engine-1280x960.jpg

These engines are the Peugeot and Audi V12 diesel Le Mans prototype engines. They are both 5.5 litres and make between 550 and 700 hp. They use particulate filters for no smoke and can't make the 700ish number except in qualifying, that much during the races and the filters clog up and choke the engine. Those HP numbers might not sound huge but consider that they are breathing through 2 39.9mm (1.56 inch!) restrictors and are limited to 2.94 bar absolute of boost (about 28 psi depending on barometric pressure). You can see the restrictors on the Peugeot pics. Details are scarce on both of the engines, a WHOLE bunch of money is invested in these programs, but the consensus is that they rev to a max of about 5500 and judging by the gearbox development issues they make on the up side of 600 lbs/feet of torque. Anyway... have a look at the plenum size on both engines, then have a look at the size of the intake runners on the Peugeot. Runner volume will affect the RPM's where cylinder filling is most efficient. I don't know what the huge plenums are doing, they are alot larger than what you'd find on a gas powered turbo race engine. But.. seeing that both of the current major league diesel race engines have big plenums, it makes you think something might be there.
With the stock 6.5 intake manifold you've got two very different port volumes which should give two torque peaks, but I suspect the volume of the 4 center cylinders is so low that the engine can't rev hi enough to take advantage of these. It would be interesting for someone with an engine dyno to play around with intake volumes. Everything from no manifold to long tubes. The engine doesn't need a turbo for the dyno. I guarantee there would be measurable differences and interesting stuff to learn.
Anyway.. lots to think about.

[67_C-30]

There are some things that won't jive between gas and diesel engines, but intake and exhaust tuning concerning port volumes and volumetric efficiency will still apply. It's a little harder to think about the lower RPM ranges but the rules are still there. Have a look at these pics:

http://www.seriouswheels.com/2007/2007-Peugeot-908-V12-HDI-Engine-Side-1280x960.htm

http://en.wikipedia.org/wiki/Image:PeugeotV12HDiFAP_3.JPG

http://www.seriouswheels.com/pics-2008/a/2008-Audi-R10-TDI-Engine-1280x960.jpg

These engines are the Peugeot and Audi V12 diesel Le Mans prototype engines. They are both 5.5 litres and make between 550 and 700 hp. They use particulate filters for no smoke and can't make the 700ish number except in qualifying, that much during the races and the filters clog up and choke the engine. Those HP numbers might not sound huge but consider that they are breathing through 2 39.9mm (1.56 inch!) restrictors and are limited to 2.94 bar absolute of boost (about 28 psi depending on barometric pressure). You can see the restrictors on the Peugeot pics. Details are scarce on both of the engines, a WHOLE bunch of money is invested in these programs, but the consensus is that they rev to a max of about 5500 and judging by the gearbox development issues they make on the up side of 600 lbs/feet of torque. Anyway... have a look at the plenum size on both engines, then have a look at the size of the intake runners on the Peugeot. Runner volume will affect the RPM's where cylinder filling is most efficient. I don't know what the huge plenums are doing, they are alot larger than what you'd find on a gas powered turbo race engine. But.. seeing that both of the current major league diesel race engines have big plenums, it makes you think something might be there.
With the stock 6.5 intake manifold you've got two very different port volumes which should give two torque peaks, but I suspect the volume of the 4 center cylinders is so low that the engine can't rev hi enough to take advantage of these. It would be interesting for someone with an engine dyno to play around with intake volumes. Everything from no manifold to long tubes. The engine doesn't need a turbo for the dyno. I guarantee there would be measurable differences and interesting stuff to learn.
Anyway.. lots to think about.

Very good info. It would be interesting to see the difference. If the same intake tuning same does apply, the dual plane intake should make more low RPM torque. I hope to dyno mine once it is finished, and if I get the opportunity, I would like to do the research on the different intakes since I have all 3 styles.