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Heath Diesel's Bonneville truck is detailed in maxxTorque: a few questions

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chi2

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The article on Bill Heath's/Heath Diesel's Bonneville truck was a fun read and the truck looks great. I will be rooting for Bill and his team to exceed 130 mph for a record:thumbsup:!

I was left confused about the logic behind some of the engine build features, and hopefully the knowledgeable folks here can help me understand.

The article stresses that Heath's truck had to include a stock 6.5L TD: "The 6.5L engine must be in stock original configuration (stock block, crank, rods, pistons, heads, cam, etc." (p. 24; maxxTorque, Summer 2008), but the actual build seems to deviate quite a bit from a stock configuration. For example, the crank is replaced with a SCAT 9000 series crank, the pistons are replaced with Mahles, which have a special ceramic coating, custom headers, two turbos and some hydraulic concrete coating for the cylinders and crankcase (to name a few :eek:16:). In addition to the core engine features, there are many additional modifications, a la the HDP products (TM, FASS, water injection, HO injectors, cold air intake and more).

Perhaps I do not understand the rules for the Bonneville race? Do racers need to have (nearly) stock engines for the "B" class diesels? Does their engine classify as nearly stock?

Did Bill and his team want the truck to be a model for others looking to upgrade with Heath products, and therefore wanted to keep the engine build within reasonable reach for the "ordinary" folks?

The biggest question for me is about engine compression: Why didn't Heath use 18:1 compression? Many of the knowledgeable engine builders on this (and the old) website move to an 18:1 compression ratio, but this is suspiciously missing from the Heath truck.

Jon
 
All the parts you named aren't modified parts, just replacements, probably why he didn't go 18:1 as that would not be stock anymore?

The replacement pistons/crank etc are built to Stock Configurations, they just aren't CHEVY Parts if you will.
 
My guess is Matt is right...
18:1 is no longer stock, the other parts are replacements and better parts, but not "different" per say than stock...
 
If there was a simple way to summarize Heath's approach to power without lowering compression, would it be based on the hydraulic concrete coating for the engine?
 
More with less

Heath doesn't rely on more boost than the GM-x turbos can produce so cylinder pressures remain within constraints of what block can support, they blueprint a engine build, and make sure the engine cooling system can remove heat, timing/fuel/boost/trans shift points are maximized to what works for them, their belief is that 18:1 is unecessary for most, mpg & starting are compromised when dealing with GM-X boost levels, that is quick summary give them a call to get full story
 
Thanks TD. I do speak with Ian and Todd, usually when I order (I am a HDP parts-junkie, btw :rofl: ), but I have yet to be given a good answer about their overall conceptual engine building philosophy.

The closest was when Ian intimated that they were looking at higher compression (than stock) engine builds for more performance. I think that this information is WIP, and I thought some of you would have a better idea about their secret sauce. I am quite excited about their speed run, and I'll be rooting for their truck. I'm sure that there will be more behind the build, should it break a record.

Jon
 
FWIW, my former bro in law has a machine shop and told me a while ago that he rubuilt a 6.5 (no turbo) for a guy. He had to deck the block (mill about ten thou off) and when he got it back together, the customer said it ran like crazy, way better than before. So I would assume that somewhat of a higher CR might be a good thing, but we have the whole 18:1 thing goin on too. Which band wagon do I jump on??
 
if going with stock boost I'd stay with stock CR, it is what I did, I had a set of 18:1s ready to go in the block, spent some time on phone with Bill & he convinced me stock was way to go, what do you plan on doing with the truck may help to decide which way to go, I've heard arguments for both for & against 18:1 I see merits in both POV's, highest legit 6.5 dyno numbers I've seen have come from "Boys at Heath" according to them many miles on performance runs & HD towing @ higher than factory GM boost levels and stock CR prior to last run Ian made with all bells & whistles, so IMO they must be doing something right.
 
True that. But now my next question. Tim your running stock CR and Slim's got 18:1's. You both have mitzu turbos. You both have pulled some enormous loads, both have I/C's, both run a chip/reflash...

So the only real diff is CR (that I can see). I wonder if Heath could tweak the HP4 for use w/ 18:1's..

Now, Matt over at Peninsular is a big proponent of the 18:1's and Bill is big on stock CR. Can they both be right? or is it more of application?
 
You also need to remember that PENINSULAR deals in marine applications mostly. Marine is a whole nother ball game from MOST auto uses. In a marine app the engine is always at a high engine load level as they are propped to run just under max RPM's at WOT. So essentially they are running the engine at 90%+ power at all times. In this instance the lower compression can really be utilized since the engine is always under high loads. 18:1 does yield somewhat lower efficiency under light loads due to the lack of cylinder heat causing a slightly slower burn, this is also why they are harder to start as there is less heat available at 0 boost.

The whole point behind the 18:1 VS 21.3:1 is more CFM of airflow through the engine while still maintaining the same cylinder pressure. A stock 6.5L is set-up to run at roughly 1.5 atmospheres of cylinder pressure from the factory. 14.7 PSI is atmosheric pressure at sea level and a 6.5 runs roughly 7-8 pounds of boost, this equals 1 1/2 atmospheres in the combustion chamber under load. So lets say hypothetically that your compression is 400 pounds with no boost, at 7 pounds of boost you should have 600 pounds of cylinder pressure(I realize this isn't exact, just a representation only). This would be the safe cylinder pressure level that a stock engine was designed for. Now let's say that the 18:1 lowers your cylinder pressure down to 340, you could now run 8.3 pounds of boost and still maintain your same 600 pounds of cylinder pressure. At 8.3 pounds of boost you are now pushing 18% more CFMof air through the engine which would allow for 18% more fuel to be able to be safely burned.

Now these numbers sound low, but when you consider that a stock 6.5 in good health should easily be able to handle 12 pounds of boost, at 18:1 you could run 14.2 pounds of boost at the same pressure. And as you increase your boost you can also increase your fuel as you now have the air to burn it.

But on the flipside though, at low engine loads you have low boost. So your 18:1 is now essentially going to have the same compression as a worn out stock 21.3:1. Hence the reduced efficiency at reduced power levels. It all boils down to what will the engine be used for, and what do you expect from it. This is why I believe INTERNATIONAL chose the new 20.2:1 compression ratio for there redesigned engines. It still gives good compression for efficiency, while lowering the cylinder pressures down to a safer level.

All of my numbers are POOMA for representation only. I realize that the actual figures would have to be based on much more than just basic formulas to properly calculate cylinder pressures at given boost levels.
 
"WoW"... This is really starting to be something to get our teeth into.... what do you think... SnowDrift....?
 
How about a comprimise of about 19 to 1 using .010 thicker felpro head gaskets and .010 reduced deck height Mahle pistons which are same price as the regular ones.
 
"Wow" is right! I am beginning to see the different points of view more clearly. Thanks for the great information, and thanks to THEFERMANATOR for putting some numbers into the mix--it helped me wrap my head around what we are talking about.

Jon
 
placed my order on the 22nd and haven't gotten it yet...checkin' mail box everyday like Ralphy in the chrismas story...LOL
 
ghitch75 said:
placed my order on the 22nd and haven't gotten it yet...checkin' mail box everyday like Ralphy in the chrismas story...LOL
Click to expand...

The best part was Ralphy's response when he figured out the decoding pen was part of an advertisement! :biggrin5:
 
got them in the mail last night:thumbsup:...man 5300 rpm's on a 6.5...that thing will be scremmin'!!!!.....would like to be there to hear it!!
 
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