Cylinder Head Questions

[juddski88]

What this latest trans build will hopefully show is that its not just in the trans tuning to make it feel more streetable...we'll see. But actually, our biggest streetability gains came from tbiq and tliq and smoothing everything out. That was in sept/Oct. Bringing the shift points up helped at WOT a bunch, as well as someoother changes, but i actually preferred to daily drive the stock file.

 

[juddski88]

What I learned was high RPM erodes the pistons faster than low rpm.

My fantasy was to come with a way to run stock rods at 750rwhp reliably by pushing the peak RPM over 4500 to reduce the torque. While the test engine did have rods in it, I was going set up a stock engine if the tests worked right.

I gave up. But I learned something.

But, did you ever try a different porting theory on the heads? I'm being serious, i know you probably didn't, because of friendship/sponsorship, and that's fine, but i really really don't believe my piston pitting was caused because of rpm...time will tell and I'll report on it when i can

 

[McRat]

If you think about it, it makes sense. Airflow under the piston reduces the oiling of the piston racetrack loop, and you are putting more heat per second into the piston to boot.

For 5000 rpm operation, I want ports that have 33% more cross-sectional area. That's not going to happen on Dmax factory heads.

Understand aluminum heads crack pretty easy. This has been known for 50 years.

It would be cool to build a true 6000rpm Duramax, but you'd need to look at modern 6000rpm cylinder heads, like LS1 heads or Ecotec heads. The Dmax heads are for torque.

 

[blk smoke lb7]

I am neither a head porter nor a performace guru,truth be told i get my some of my most valuable info from you guys on DD:hug:.I am a huge believer in head porting,flow is flow and makes more power.The guy that ported my heads used to port for nascar,he explained he used to port the heads for the track that was being run a tight track was ported for torque coming out of the corners and driving hard to the next corner not far away,big tracks with long straights were ported for high horsepower for running double century #s.So i do believe there is not a 1 head port does all,he asked my goals with the heads and i told him to run the best 1/4 mile times i can at the strip.My truck ran 11.64 last run,last outing of the year i feel theres more to it yet and i did it with rather cool egts i have been finding the higher the rpm before the shift seams to be making for power.Head porting isnt the horsepower it makes use of what you already have.We did a head gasket job on a 02 lb7 the truck had a 7 inch lift 37 inch claws 13 mpg and had normal turbo lag after fresh heads with porting nothing else done the truck got 16.5 mpg hand calc. and the truck was extreamly responsive.I know head porting works you just have to justify the $=horsepower alot of people dont think its worth the $ thats their choice.Take my findings for what they are i am no means a professional in this sport i try to do alot of research and find what works for me and the peoples truck we work on.And i am not here to bash or knock anyone here just to be clear.

 

[PACougar]

Here's what I don't understand, if I made a product that performs xyz I wouldn't hide that information, I'd sing it to high heaven! If you port heads, why wouldn't you want to make how great your product works known to everyone? I'd understand if we were talking about some trade secret(i.e. how you port them or some special tool or technique), but we're simply talking about how they perform. Who cares about how a shops heads perform on some customers truck, way too many variables to compare how good the heads are.

 

[blk smoke lb7]

I have a sheet somewhere around here with the stock flow vs the ported flow mine picked up 30 cfm intake and 60 cfm exhaust if you want to call the guy that did mine he will show you the results and when you get a set of heads he includes the flow sheet from your heads to prove what your getting.In my case i didnt dyno my truck before and after and i did twins shortly after getting the truck running again.

 

[CurtisEmery]

what type of flow bench is each using? have any graphs from any source been provided to prove claims?

Another thing to keep in mind, a flow bench does not simulate what is going on inside the cylinder. In my eyes it is more of a marketing tool than anything else. At the end of the day there is no replacement for real world testing. And I if I was looking for flow improvements it would be at lower lifts. Peak flow numbers are very decieving, one needs to look at the whole intake and exhaust event to see the whole picture imo. You really need to dyno that thing, that will tell you if it is making more power or just feels that way. I also would likeep to say that pat is right on the money about the turbo. Larger exhaust wheels and a/rs coupled with a big comp wheel will change the power band more than any porting or cam. I bet if you put a 1.25a/r on that thing your peak would be much higher, I doubt it would be much fun on the street though....

 

[juddski88]

That was my whole point of posting. The Current marketing of cookie-cutter heads and cams is dated....the competitors, like most of us are, need more. David, and other small shops around the country provide that, but that doesn't pay for the 5 axis CNCs or the private school tuitions or the monthly vacations...so what happens to the ideas that work? They eventually get kicked to the corner and nothing is allowed to be discussed in public...the complete opposite of the mission statement of Pat and Kat's forum

 

[CurtisEmery]

Just some food for thought.... How would you feel if you spent countless hours developing a product, and have someone up and copy it and call it their own. I would venture to say it would discourage you from investing time and money to improve upon what already works. Things aren't as they always appear. You need to look at both sides before forming an opinion. I'm sure there are other great options out there for head porting, I have ran socal stage2 heads for 4 years trouble free! Running very large single chargers and plasma hot egts the engines entire life. I would say they are a very viable option for anyone looming for cnc ported heads.

 

[juddski88]

That is certainly true, i felt as though i took that into consideration though, and i will not keep my findings to myself like most do. I am brutally honest about anything i do, i surely admit to not knowing everything, hell, i barely know anything about what people have tried and what has and hasn't worked. But i am not the only one who has seen these gains from switching to a different head style and cam than Guy's. Another fine example is Rob Hall. And another is Wes Kuselik. And another is Matt Handwork....the list goes on and on. And like i said earlier, this mostly applies to big single chargers that are not forcing enough air into the cylinders below 3000 rpm..

 

[bubba2400]

A couple of quick notes before I leave the shop to watch my daughters high school soccer team play.

Actually a CNC program is developed so that the flow and performance results can be duplicated repeatedly.

Hand porting is anything but repeatable, especially on a set of heads that has 32 valves.

Hand porting is how we do our prototype work, after spending hundreds of hours getting the port just right, the ports are digitized and a CNC program is developed so that those results can be duplicated time after time.

The stock casting is really the limitation. You can only go so far before you have a great flowing set of heads that don't hold water.

I've been hearing this same line of shit for 30 years.
Those shops that can not afford to invest in the equipment/technology to CNC port cylinder heads have no way to compete other than trying to tear down and cast doubt on the CNC process itself.

Guy

Guy,

Thanks for the post. I do understand that the CNC is just a big copy machine for the most part and is the best way to get consistent ports. And I would be fine with a CNC head that was tailored for a specific application, something like RFD does with it's gas motor heads. Do you guys do that or are there only the three or four options for porting? And I realize this is probably not the most profitable thing for a business, just wondering if that is an option.

Also good to hear that the cylinder head is more of the limiting factor. That is good to hear from someone with experience. Thanks again for the post.

 

[juddski88]

There's several 1200+ hp duramaxes with singles and twins and triples with stock heads...so a limitation? I dont see it...

 

[ChevyDieselLLY]

There's several 1200+ hp duramaxes with singles

and twins and triples with stock heads...so a limitation? I dont see it...

I think the limitation is the design of the stock head. You can only do so much to it

 

[Dirtymaxx03]

Is there any numbers that show who has the best flowing head? Say a guy like myself wanted to build a high rpm, single charger stroker motor, where would I get cylinder heads that could flow the amount of air that would be required? Or is that getting into the super high dollar custom secret squirrel billet stuff?

 

[quadracer37]

There's several 1200+ hp duramaxes with singles and twins and triples with stock heads...so a limitation? I dont see it...

I agree. I made a 1000 with stock heads and cam only reason I'm getting my heads ported is to help lower my boost numbers because 100+ is hard on shit!
Unless its a 100% all out build looking for every bit of power, I think stock ports are fine and the money is better spend on fuel and turbos.

 

[Stingpuller]

Heads

If you guys really thing that ported heads make that much differance then I guess you already have your answer. Thanks for your post Pat that is pretty much what I have seen myself with mine. The turbo, or should I say the TURBINE has more to do with were it makes power than anything! If you want that last 10 or 20 hp it MITE be there with ported heads. I would rather spend the money on a good turbo that will work in the rpm range your trying to run the motor. I will say it again, IF ANYONE!!!! has a ported head or cam that will pick my junk up 2 or 3 tenths I will pay ANYTHING FOR THEM! BUT, if it doesn't you will not like what i'm going to say about them. I don't mind spending money if I get something from it. It seems that that doesn't always happen. I have wasted a lot of money and I just try to give real answers. It's just not what most people want to hear. I always say if you don't want to hear the answer then don't ask the question! I run away a lot of work but I will not try to sell something that I think is a waste of money. I'm sure I could step my game up with sales/work but I like to sleep at night and not worry about who is calling.

 

[juddski88]

Like i said, ill report back truthfully what i find for dyno numbers...I'll even overfuel it like it was in denver for a few runs to get as close to a 1:1 comparison as possible

 

[CurtisEmery]

If you guys really thing that ported heads make that much differance then I guess you already have your answer. Thanks for your post Pat that is pretty much what I have seen myself with mine. The turbo, or should I say the TURBINE has more to do with were it makes power than anything! If you want that last 10 or 20 hp it MITE be there with ported heads. I would rather spend the money on a good turbo that will work in the rpm range your trying to run the motor. I will say it again, IF ANYONE!!!! has a ported head or cam that will pick my junk up 2 or 3 tenths I will pay ANYTHING FOR THEM! BUT, if it doesn't you will not like what i'm going to say about them. I don't mind spending money if I get something from it. It seems that that doesn't always happen. I have wasted a lot of money and I just try to give real answers. It's just not what most people want to hear. I always say if you don't want to hear the answer then don't ask the question! I run away a lot of work but I will not try to sell something that I think is a waste of money. I'm sure I could step my game up with sales/work but I like to sleep at night and not worry about who is calling.

I 100% agree the turbine side of the charger really dictates the final operating range. Everything else is just making small gains. I went from a gtx4508 to a gt4718 and picked up a solid 3-400rpm down the track. I am sure the larger comp wheel had helped as well. Spooling is the only downside I see. I am looking at possibly a gt50 turbine and a new socal cam to see how much more I can pick up in the higher rpm.

 

[PACougar]

I 100% agree the turbine side of the charger really dictates the final operating range. Everything else is just making small gains. I went from a gtx4508 to a gt4718 and picked up a solid 3-400rpm down the track. I am sure the larger comp wheel had helped as well. Spooling is the only downside I see. I am looking at possibly a gt50 turbine to see how much more I can pick up in the higher rpm.

Just out of curiosity, where did you see peak power on the GTX and what housing was on it?

 

[CurtisEmery]

Just out of curiosity, where did you see peak power on the GTX and what housing was on it?

The gtx ran good right around 4000rpm with a 1.28a/r housing sitting in the valley. Keep in mind I changed a bunch of things this year. I put dual tires on, larger headers and front mount pedestal, gt47 18r, larger a/w intercooler and 200 over sticks. Iwould say I would have picked up more rpm if I hadnt done the duals.