• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

What’s the scoop with Heath Diesel?

I think he remembered his Mom saying “If you don’t have something nice to say...”
Haha.

is that the cam Heath made for helping the offset of the turbo to the side of the engine and changed the valve timing on the driver side?
 
Absolutely Nates header is a winner. What else would be good is a long tube header from the other side with tubes coming together in a collector under Or at bottom of the pan. Then coming up in one tube. Have to do the math to see where it would be best. Trying to match the other side in inches traveled would be nice.

I thought about long tube header dropping down on the passenger side then turning and coming back up With the other one.
longer individual tubes help low end torque snd shorties help high rpm hp is rule of thumb. But getting mr turbo spinning happy is the variable to that rule.
 
A fully divided centermount is what the 6.5 should have had from the factory. The 6.5 is the only modern diesel with an open system that's side mounted like it is. A center mount would balance the exhaust. And a divided setup would allow for a larger t4 turbine housing while keeping low rpm spooling.

That opens up a whole new possibility for cam specs. The high drive pressure from the factory turbo is why the cam is set up the way it is. Can't have alot of overlap if the back pressure is twice the boost pressure. A more efficient turbo will allow the LSA to be decreased which would really help the scavenging process.

Has anyone one put the 6.5 heads on a flow bench? It would be awesome to see at what lift the there is no added flow. That way a cam can be designed around that. A little added lift, duration and a change in the LSA would really help the 6.5 when paired with a bigger turbo. I've been working on a cam for my build. But I'm not even close to putting the engine together... one day.
 
Rockabillyrat said:
That opens up a whole new possibility for cam specs. The high drive pressure from the factory turbo is why the cam is set up the way it is. Can't have alot of overlap if the back pressure is twice the boost pressure. A more efficient turbo will allow the LSA to be decreased which would really help the scavenging process.
Click to expand...

Back in the day when I raced often I did use a massive amount of of overlap on gas fueled turbo 2.3 ltr and high pressure water injection to beat back pinging so timing stayed advanced. I was shocked with the results massive increase of torque and performance however; fires in the turbine and exhaust became the issue it got too be pricey but man what fun it was.......
 
@Rockabillyrat after the major choke point of the turbo gets removed the rest of the awful airflow design on this engine starts to limit you. X2 on the 'slap something on' exhaust airflow abortion GM came up with. Even Banks had a better manifold for the 6.2 and 6.5 NA turbo kits.

Several people including @Twisted Steel Performance have done flow bench and head improvements. Safe to say the stock heads are well known for leaving HP on the table.

There was lots of room to improve this engine by the aftermarket. The resistance to any better turbo's alone (on this engine) was a good example of the research waste doing so would have been. Likely why so little aftermarket improvements were available in the pre Duramax years.

Dodge Cummins tossed a sewer pipe on for an exhaust one year and ever since. I wish GM was dumbfounded by Dodge doing that... But biased on continued GM ignorance of airflow in the intake/exhaust I doubt GM even bothered to care. When GM did care they gave us a quarter sized "cold air intake" hole to feed a LS2 in a Trailblazer SS. :facepalm::eggface:
 
Exactly, after the turbo and exhaust is upgraded the real hold back on the 6.5 is the heads and camshaft.

I would love to see a chart with port flow at various increments of valve lift for a stock 6.5 head. There comes a point where adding lift doesn't add additional flow because the head is the restriction. At that point port work is needed to increase the flow. So knowing at what valve lift does the port flow stop increasing would be very helpful in the development of a performance camshaft.

I spoke with a guy that was heavy into drag racing grand nations. The class rules stated the stock camshaft lift and duration had to be used. Never said anything about the LSA. He told me a few degrees of change in the LSA made a HUGE difference in how that car performed when combined with a more efficient turbo.
 
Last edited:
Oh and while we are on the subject of Heath Diesel. For years people are talked smack about his "500hp" salt flat build that was in the magazines. Everyone, Including myself said it was impossible. Especially with a DS4 Injection pump..... well I've been researching injection pumps for a little over a year. And for the fun of it I tore apart a locked up DS4 just for fun. Well, its definitely possible to build a DS4 to push enough fuel for 500hp. It's so incredibly easy I'm surprised no one else has done it yet....
 
ak diesel driver said:
Well we're waiting.lol
Click to expand...


Can't give away all the secrets...

But I will say this, there are 4 things needed to make this pump a reality

1. Need to be able to do your own tuning. Since the fueling output will almost triple over stock the pulse width will need to be adjusted.
2. Need one part from a different pump model. They are $500 new, or buy a core pump to take it from for alot cheaper. (I have 8 of those part sitting on the shelf in my fuel room)
3. Find a EDM shop willing to take on such a small machining job. The part from the other pump will need machined to work.
4. Lastly a pump builder willing to put together a DS4 with modified parts. I'm certain they wont give you a warranty because of that. I have no intentions in building DS4 pumps. I've dropped enough money on DB2 tools.

If anyone is willing to put up the money and time send me a message. I have the part and can probably get it machined. You would have to find a builder and have the tuning software to make it run.
 
I thought the 6.2 cam was same as6.5 cam so it was not built to help yonder turbo as the nearest turbo was on a competitors truck.

as to the turbo being center mount and that in itself solving a lot of the issues, gonna say nope to that. Gm6 sidemount is same spec as gm6 center mount. It created confusion in parts reference so when the gm7 came out trying to help hummers, the same spec was used and became gm8. So 6=6 and 7=8. And the difference in power of centermount 6 vs side mount 6 is so negligible that matched pop level injectors have bigger impact.

now centermount a big t3 or normal t4 turbo- heck yeah!

Bill contested the side mount was the big design reason for change of one of his cams.
 
Rockabillyrat said:
I would love to see a chart with port flow at various increments of valve lift for a stock 6.5 head. There comes a point where adding lift doesn't add additional flow because the head is the restriction. At that point port work is needed to increase the flow. So knowing at what valve lift does the port flow stop increasing would be very helpful in the development of a performance camshaft.
Click to expand...

Well your in luck, I have been porting these heads for many years and have flowed countless heads. I have posted charts here and other forums many times.

Several years ago I knew of 2 other shops that offered porting, Diesel Depot & Peninsular Engines, Diesel Depot is long gone, Peninsular may still have another shop other than me that will do it, not sure tho...

I flowed heads from late 80's all the way to new P400's and aftermarket, and ported from the 2 other shops to compare my numbers with, I still have most of the charts as well .

I have slowly been increasing the flow as well as cc volume in the runners, and I cut a P400 head apart to confirm they are really different castings than GEP heads, yes I cut a 1K head in pieces so I would know for sure...

I currently have 1 new set of box stock heads here, they are in line as we speak to be flowed, this time a little different, I'm having the numbers taken every .050" lift all the way to .500". Then, my personal set will be flowed the very same way, but mine have the largest intake & exhaust valves possible. This run is two fold, the low lift numbers are as important as total lift is, and for those that want to know want a maxed set of heads can flow..

The below chart shows a stock 2003 GEP head with minor porting, as you can see the stock heads drop off or max out and fall, the others don't ... and this was a progress checking flow not finished work... The exhaust side is where I have been working to develop the greatest gains...

GEP Stock VS Ported.jpg
 
They are the same camshaft. My point was that there can be improvements made to the factory cam to get more benefits from switching to a more efficient turbo. Gm probably didn't bother to redesign it because it worked with the setup they had.

The factory 6.5 centermount didn't fix much of anything. In my opinion it should have been a T4 from the factory.

Thanks @Twisted Steel Performance that's exactly what I wanted to see!! It looks like the stock cam has enough lift to almost max out the flow capability of the stock GEP heads. That's really good information to know!!
 
Last edited:
So it sounds to me like your putting bigger plungers in and then using a 5068 cam ring. I tried to get Slim to sell me his bigger plunger head but he said he would only sell it as a complete pump. I was OK with that and he said he was having a pump builder put it together. According to Slim the builder couldn't get it to work right. All second hand info so I don't know maybe he changed his mind and didn't want to sell it
 
I've been down the cam road as well, I machine reliefs in pistons for a reason.... ;)

Their is a lot most don't want to accept about these motors, 1 - 20:1 compression kills.. 2 - you need more room in the cylinder to give room for added fuel and more air, you only add cylinder pressure otherwise...

In stock form their is not room to change much in the way of the cam, I have cam specs from a "cam doctor" from several as well I could post again, all the stock cams are the same, never a change...
 
You must log in or register to reply here.
Back
Top