Pre combustion chamber design research

[Rockabillyrat]

That’s awesome you guys are close enough to work together. That would be so cool to see a complete flip of things. It’s like the crankshaft debate cast vs forged. There was evidence pointing toward both sides. Some folks still on opposite sides, mine- well only one style survives in top fuel...


@n8in8or It’s just a money thing why there isn’t that much dyno info. And the fact that you aren’t selling things is why you can’t pour money into the proof of a dyno. Say you sold custom parts like your header or you rebuilt and sold turbos. You could dyno your set up with a stock manifold and get the comparison, cost maybe $1500 counting labor. Then that gets paid for out of selling headers- But how many? Same for turbos.
Now if you just do 0-60 or 0-100 runs and maybe track mpg of 1 tank each way, that is much cheaper. But it isn’t documented unless a video- then that could be questioned just like people question a dyno run.
But those who believe the story and based on your results, some folks would buy from that.


Crossing my fingers one of you stumble on a $100 pickup with 6.2/6.5 parts in the bed. I really wish I had the big parts pile still to donate, unfortunately it all got donated long ago.


Wait, Labscope? That sounds like a dedicated thread itself full of wowed moments.

The labscope has been an idea I've had for a while. All it took was a few beers and mowing the yard for me to figure out the last peice of the puzzle. I'm actually more excited about this than my injectors. Might even make the DS4 guys a little jealous.

 

[3500_6.5]

I only read the beginning of this thread, so I know I missed some things. But, the obvious reason the Fords are running more power is simple: db2. They never went electronic. All of their engines stayed mechanical. That is essentially the key to all of their power. That and their engines are built maybe a tiny better than ours...

You won’t get the torque they get, but you can get just as much power out of a 6.5 as the 7.3s simply by ditching the ds4 for one of their aftermarket db2s and a quality turbo. I was on the same quest for hidden power as you were several years ago. All of the work and time spent, to be frank, was a waste. The quickest and easiest way for power is dump more fuel in and force an equally stupid amount (for a 6.5) of air into it. You’ll make more power than a 6.5 can handle by doing those two things. All the minor tweaking of injectors, pre cups, piston designs, intake flow, head flow, etc, ect, all amount to minimal gains at best that, in my humble opinion, aren’t worth the effort. Unless of course you plan on selling said parts to the 6.5 community.

I’m not trying to discourage you from trying, I was there and was all about discovering it all on my own too. And I’m all for someone finding other ways to be more efficient and gaining power, but if the end game is simply 6.9/7.3 power, turbos and db2s are your best friends. Everything else has simply been a bust in comparison.


Sent from my iPhone using Tapatalk

 

[Rockabillyrat]

Thanks for your comment. You should read the whole thread that will give you an idea what we are doing and the research put into it.

I agree a modified db2 and turbo upgrade is the best bang for your buck on a 6.5. But we are way past that. I do disagree about the other upgrades. The stock turbo exhaust manifolds and upper intake can use alot of improvement. EGT, IAT, and cruise boost pressure all benefit from upgrading both of them. And again we are way past that. Doing all of this work on a stock 6.5 would definitely be a waste of time. The reason to start playing with injectors and cups is to get over the next HP level.

At the end of the day all this work is to try and squeeze more hp out of a 6.5. But even if we don't, all this testing will finally give us real data and not just opinions. That way we can finally move forward with this platform. I have no plans to sell any parts. Other wise I wouldn't share 100% of my research online. All of this is just for fun and I want to share it with everyone.

I would love to also do a turbo shootout. Maybe some of the venders would be so kind as to let us do a unbiased competition. Holsets vs att vs quadstar vs maybe a s300 bw..... I can't afford to buy them all is the problem.

 

[ak diesel driver]

there's still $182 in the dynofund. this would be a great place to spend it IMO. Plus more could be added to it if people are interested

 

[n8in8or]

there's still $182 in the dynofund. this would be a great place to spend it IMO. Plus more could be added to it if people are interested

There's a dyno fund???

 

[ak diesel driver]

http://www.thetruckstop.us/forum/threads/dyno-fund.33899/

 

[3500_6.5]

You can literally buy an injection pump that puts out 3x the amount of a stock injection pump. It will allow you to absolutely blow a 6.5 apart with fuel. This can be accomplished with just bolt ons. I’m not saying other parts won’t help with overall efficiency and what not, I’m just making the point that if you want to make it to the next hp level, a 180cc pump gets you there. If you’re past the hp that 180cc worth of fuel gets you, then I stand corrected.

Upper intake can be improved on, yes. I ran a “custom” upper intake for my intercooler. When I changed my setup, I took it off and put the stock intake back on do to lack of room/intercooler plumbing changes when I redesigned me turbo setup. When you’re forcing x psi of boost into the combustion chamber, as long as your intake isn’t restricting said boost, it’s not going to much matter. Running both stock and essentially just a 3” pipe running into the lower intake, iat didn’t change, nor did boost. I’ve done a lot of testing. Ive spent more time than I care to mention on my current setup. I’ve changed intakes, I’ve changed rockers, cams, manifolds/exhaust/turbos. Can I say what I have now is more efficient, probably has more power and should provide for a longer engine life at those powers than before? Yes. Was it worth it? Looking back, probably not lol. The best thing about it is that I can say I have something that probably 99% of other 6.5 owners will never have or even see. Other than that, I can honestly say I could have better spent all of that time and money.

Again, I’m not saying don’t do it, I’m just trying to give you a forewarning. But if Nate is working with you, considering what he has done and already accomplished, I’d say it’s safe to say you guys know what you’re getting into with this stuff. So I’ll leave it with a genuine good luck, and any further comments by me will be solely constructive input to help out where/if I can.


Sent from my iPhone using Tapatalk

 

[3500_6.5]

I have a feeling I sound like a grumpy old man lol. I’m really not trying to put you down for what you’re doing. If you’ve happened to read my build thread....that I still have not finished... like most of the people commenting on here have, I mention in there that I found that sometimes I seem to come off as sort of an a$$ in my comments to others. That’s not my intention at all. It’s hard to give the correct emotions in what is essentially text messages on my phone. I genuinely am looking forward to what you may find, I’m just trying to give you some heads up info from someone whose been where you are. But when I started, I was mislead and given false info to begin with that set me back time and cash, so I’m just trying to give you some honest opinions from my own experience.


Sent from my iPhone using Tapatalk

 

[n8in8or]

I have a feeling I sound like a grumpy old man lol. I’m really not trying to put you down for what you’re doing. If you’ve happened to read my build thread....that I still have not finished... like most of the people commenting on here have, I mention in there that I found that sometimes I seem to come off as sort of an a$$ in my comments to others. That’s not my intention at all. It’s hard to give the correct emotions in what is essentially text messages on my phone. I genuinely am looking forward to what you may find, I’m just trying to give you some heads up info from someone whose been where you are. But when I started, I was mislead and given false info to begin with that set me back time and cash, so I’m just trying to give you some honest opinions from my own experience.


Sent from my iPhone using Tapatalk

Whatever Tim, you're an a-hole and we all know it!

For Rockabilly and anyone else that may not know, 3500's truck is the one that inspired my build. He was one of the people that showed what a 6.5 could do. Now if he'd ever finish the other build maybe we'd see what else a 6.5 could do.....

 

[Rockabillyrat]

I take no offense to any thing you said. It's very helpful constructive criticism. Getting feed back from as many people as possible was my reason behind posting on this forum. Learning from what people have done in the past is very helpful. I'm just thankful there are people on here that take the time to give me feedback. I appreciate all of it!!!

 

[WarWagon]

I would love to also do a turbo shootout. Maybe some of the venders would be so kind as to let us do a unbiased competition. Holsets vs att vs quadstar vs maybe a s300 bw..... I can't afford to buy them all is the problem.

Really you should get ahold of Dennis, who makes the ATT, who did experiment with larger and completely hogged out precups. Understandably he is sick of the drama around turbo's and explaining the trade offs of going to a big turbo that changes the RPM range. Once you understand the fing thing won't light below X RPM the battle is won. Then it stomps a "Asthma Attack" all the way to redline. IMO, cost be dammed, the ATT should offer a Ball Bearing center section.

Now I will say "Don't re-invent the wheel." Turbo's have already been tested and are a known known for the market vendors care about. This is light mods, but, close to stock. Spending what you guys do on a build the turbo is going to be closely matched to the build.

That said showing improvements to the engine that make the turbo work better is a new area. As much as I enjoy reading about the topics you bring up and also encourage you: "So What?" as I can't really buy a off the shelf aftermarket set of improved manifolds like @n8in8or is running. Head porting appears to be available and does make power period once the other airflow problems GM hacked together for us are removed. Vendors are listening and I don't care who decides to make it, but, someone really needs to do so. You are looking at precups while the rest of us still have the GM Airflow Abortion turbo manifold.

@3500_6.5 is spot on for a point where money is spent better elsewhere.

Pulling heads of a 6.5 for most is a dammed big deal. It's not far from pulling the complete engine. This is one reason why precup research is limited. Getting them machined is the other. Moot point when one is replacing an engine so a combo that works well for the "next engine" that goes in is of interest, if, you can get the custom parts.

The above said I again encourage you as this engine is in production and a few want to take it to the edge.

 

[n8in8or]

That said showing improvements to the engine that make the turbo work better is a new area. As much as I enjoy reading about the topics you bring up and also encourage you: "So What?" as I can't really buy a off the shelf aftermarket set of improved manifolds like @n8in8or is running. Head porting appears to be available and does make power period once the other airflow problems GM hacked together for us are removed. Vendors are listening and I don't care who decides to make it, but, someone really needs to do so. You are looking at precups while the rest of us still have the GM Airflow Abortion turbo manifold.

This is a good comment. It would be great to do a back-to-back test with the header to see what it does. I'm not sure it helped power at the DS4 power level, but now that I'm above that level it would be cool to see what it does. Either way, testing should be done at multiple fuel levels to see for sure. Included in that test should be an evaluation of temperatures in cylinder 8 somehow. I still have the fixture, so if enough benefit and interest is found, more could potentially be made.

 

[WarWagon]

I still have the fixture, so if enough benefit and interest is found, more could potentially be made.

We are blasting half the engine exhaust past two 90 degree exhaust ports and 1/4 of the engine into the (90 bend) 180 ports where it needs to go the other way including the #8. As the spool valve ruined engine oil for me it's clear that holding exhaust in the engine increases temperatures. The benefit is clear and really doesn't need testing. Assuming the "Asthma Attack" turbo is already gone. Just no gain to be had with a GMx in the way.

Recall exhaust volume at 1100 degrees is way greater than intake volume at 300 degrees so one should start with exhaust improvements unless you have a LLY type OEM screw up going on.

Partner up with @Burning oil and put a price tag on it. At one time the driver side OEM Abortions cost $500 alone, but, looks like knock offs are available cheaper now. So at what price point is it worth your while to build more and how many you want to make?

 

[Rockabillyrat]

I've spent so much time focusing on what's going on in the chamber I neglected to look into the relationship between the cup throat and channel in the piston. It's easy to see that the two small machined dishes and channel direct air into the chamber on the compression stroke. So when it reverses flow the flame front is concentrated at the channel where it directs it to the two dishes causing a dual swirl in the cylinder. The wider the cup throat the larger the flame front area. There could be a point where a larger throat is concentrating to much of the flame front out side of the channel. And it could have an affect on the swirl and combustion in the cylinder. Here are a few pictures to help explain where I'm coming from. I would like to measure the channel width and compare it to the n/a cup throat width.

 

[n8in8or]

I've spent so much time focusing on what's going on in the chamber I neglected to look into the relationship between the cup throat and channel in the piston. It's easy to see that the two small machined dishes and channel direct air into the chamber on the compression stroke. So when it reverses flow the flame front is concentrated at the channel where it directs it to the two dishes causing a dual swirl in the cylinder. The wider the cup throat the larger the flame front area. There could be a point where a larger throat is concentrating to much of the flame front out side of the channel. And it could have an affect on the swirl and combustion in the cylinder. Here are a few pictures to help explain where I'm coming from. I would like to measure the channel width and compare it to the n/a cup throat width.

View attachment 53153
View attachment 53154
View attachment 53155

Interesting stuff. I’d never considered that relationship before.

I thought of 3 things:

1. I have a set of 6.2 pistons that I could measure the pistons crown features of. I think I got rid of my 2 sets of junk 6.5 pistons, but I’ll look again.

2. I wonder if GM changed the pistons crowns any when they changed pre-cup sizes or at least when they went from 6.2 to 6.5?

3. I chuckled every time I read “regenerative member”. Sorry, my inner Beavis and Butthead couldn’t help themselses.....huh huh eh heh huh uh huh...that was cool!

 

[n8in8or]

We are blasting half the engine exhaust past two 90 degree exhaust ports and 1/4 of the engine into the (90 bend) 180 ports where it needs to go the other way including the #8. As the spool valve ruined engine oil for me it's clear that holding exhaust in the engine increases temperatures. The benefit is clear and really doesn't need testing. Assuming the "Asthma Attack" turbo is already gone. Just no gain to be had with a GMx in the way.

Recall exhaust volume at 1100 degrees is way greater than intake volume at 300 degrees so one should start with exhaust improvements unless you have a LLY type OEM screw up going on.

Partner up with @Burning oil and put a price tag on it. At one time the driver side OEM Abortions cost $500 alone, but, looks like knock offs are available cheaper now. So at what price point is it worth your while to build more and how many you want to make?

I’ll look into it....

 

[Rockabillyrat]

Interesting stuff. I’d never considered that relationship before.

I thought of 3 things:

1. I have a set of 6.2 pistons that I could measure the pistons crown features of. I think I got rid of my 2 sets of junk 6.5 pistons, but I’ll look again.

2. I wonder if GM changed the pistons crowns any when they changed pre-cup sizes or at least when they went from 6.2 to 6.5?

3. I chuckled every time I read “regenerative member”. Sorry, my inner Beavis and Butthead couldn’t help themselses.....huh huh eh heh huh uh huh...that was cool!

Exactly what I was thinking. I'd like to measure out the pistons and cups. As well as cc the cup volumes. It would be interesting to compare them all to one another.

 

[WarWagon]

http://www.thetruckstop.us/forum/threads/idi-tecchie-info-courtesy-of-great-white.27096/#post-323250

In case you overlooked it.

This is one engine that you can increase MPG and performance on at the same time. Because when you work it the GMx turbo turns fuel into heat. Example MPG foot on floor for 550 miles towing grades. I raised the MPH and MPG on grades with an ATT turbo. So better airflow can raise both power and MPG.

In depth turbo results...
http://www.maxxtorque.com/2012/07/the-65l-diesel-factory-equipped-asthma.html?m=1

 

[n8in8or]

http://www.thetruckstop.us/forum/threads/idi-tecchie-info-courtesy-of-great-white.27096/#post-323250

In case you overlooked it.

This is one engine that you can increase MPG and performance on at the same time. Because when you work it the GMx turbo turns fuel into heat. Example MPG foot on floor for 550 miles towing grades. I raised the MPH and MPG on grades with an ATT turbo. So better airflow can raise both power and MPG.

In depth turbo results...
http://www.maxxtorque.com/2012/07/the-65l-diesel-factory-equipped-asthma.html?m=1

The links in Great White's thread don't work anymore.

 

[Rockabillyrat]

I started looking into emission standards set in place in the 1990s. With today's modern diesel engines it's easy to see the evolution of emissions equipment as the laws changed. So I thought if GM really did design the 6.5 cups and injectors for emissions control I might find a pattern.

Diesel emission standards remained mostly the same from the start of the Clean Air Act (74) all the way to 91. That year a reduction in particulate and NOx levels was enforced. One year before the 6.5 was introduced. Then in 94 particulate was reduced even more. The same year the DS4 was introduced. And finally in 98 NOx was reduced again. One year after they switch to the diamond cups on the F Vin.

In 97 a law was passed for the 04 emission standards. Giving the manufacturers 7 years to come up with a platform to meet them. In comes the LB7 which was the base for the LLY that was brought out in 04 to meet the new standards. So you can follow the evolution of the GM diesels all the way back to 91.

GM offered the Banks Sidewinder as a dealer option from 89-92. It claimed a 60hp gain. Putting a 6.2 under perfect conditions around 190hp. The 6.5 was rated at 180hp. Now I understand why GM attempted to design their own turbo system. It was much cheaper than having Banks supply it for them. But why change the cups and injectors? Obviously it wasn't to make more power. Well if you ask me they were changed to meet the new standards set place in 91 and nothing else. The more I dig into this subject the more I'm convinced that 6.5 cups and injectors are emissions friendly and have nothing to do with performance.