I'm currently making plans for a high performance forced induction engine.

This isn't something I'm doing next week, more like NEXT winter (2005/2006), so there's no real rush. I'm just trying to put a lot of time into research, so I don't get the thing halfway done and then learn something that makes me wish I'd followed a different path.


My current engine is an LTx, and while I haven't ruled out baseing the buildup on that, I think that I may want to take advantage of the many advances that have happened in the decade or so since these engines were first designed.


I figure that there are two potential paths to take:

1) LSx based engine, with either a 6.0 liter truck block or an aftermarket aluminum block, and aftermarket heads.

2) Gen I design with aftermarket Block and Heads.


On the first option, I think that beginning with a 6.0 liter truck block might be a good way to start, but I don't honestly know whether or not there is an aftermarket aluminum block that might be a wiser choice. More importantly, I don't know what the limitations of the heads might be. For instance, I see that A.I. has an LSx head that flows in the 300/210 range, for a 70% exhaust flow, but on a forced induction engine using a centrifugal supercharger, I'd like to see a higher percentage on the exhaust flow.

On the second option, I was looking at the Dart Little Chief heads, which look very interesting to me. I can't help thinking that this may very well be the ultimate SB type head, and there seems to be a bit more room to work with in terms of getting a higher percentage of exhaust flow, without sacrificing a lot on the intake side. However, while this head looks great on paper, I really don't know what the reality is.


The question essentially comes down to this; which of those two basic options would be the most appropriate for my plans?


To narrow the question sufficiently that I can get a meaningful answer, here are my plans:

a) I have decided that, in terms of packaging size and fitment within the engine bay, a small block is probably a better choice than a big block. Another consideration is that if I were to use a big block I would not only be looking at a heavier combination, but the weight would be shifted forward in the chassis as well. So for this particular application, I believe a SB is the better choice. This still of course begs the question; is the Gen I or Gen III option the better path to follow?

b) I want to run at least a 3.75" stroke, for the torque advantage, but I also want to get the rod/stroke ratio as close to 2:1 as I can, which in my mind means at least a 6" rod. I am mindful that in the LTx block, in a forced induction application, most people limit themselves to a 5.85" rod specifically to avoid a top land that is too thin. I am uncertain which of the two options I mentioned at the beginning of this post would tend to allow the better ratio, although I suspect that it's the second choice.

c) This buildup can in no way be described as cheap. However, to the extent that is possible, I want to choose "off the shelf" parts and combinations, as opposed to "custom" ones, which would tend to be more expensive. By using this strategy, I hope to hold the costs down as much as practical in what will be an expensive build no matter what I do, but I'm not sure which of the two choices better lends itself to that strategy.

d) I do not plan to build this engine with a particular HP goal in mind, although I suspect it will approach and possibly pass the 1,000hp mark.
Instead, what I want to do is try out some ideas I have been kicking around for a while, in order to see where it takes me. I want to repeat that, because it's very important... This engine is MEANT to be experimental and unconventional because I WANT to build it that way.
My intention is to build an engine with a relatively low RPM range, in deference to the reality of F=MV^2, with a redline probably around 6,500rpm.
On top of this I intend to intentionally use a head that's too large for the displacement and camshaft, with a centrifugal supercharger that's too large for the head, in order to take advantage of the volume of airflow it can put out. However, at this time my plans are to use relatively low boost, probably on the order of one Bar. I may decide to use more boost later on, but this is specifically NOT meant to be a high pressure engine. I specifically want to build it with a different philosophy.
I also plan to use a cam with the 4/7 swap and I'm hoping to use a "Miller Cycle" timing pattern to lower pumping losses, although I am only in the very early stages of researching that.




Taking all this into account, including any issues that I may be unaware of at this time, which of these two engine options would be more suitable to my plans? The Gen I option or the Gen III option?

 

Thoughts:

1000hp. No vehicle or performance goals specified.No budget specified. "Off the shelf" parts prefered. Miller Cycle engine desired.

Whew!

Perhaps you might define your goals first, including vehicle and performance desires, specify a budget, and let the engine gurus go at it. The fewer restrictions you place on an designer, the easier it is for him/her to offer a solution.

Gen I offers many more parts options than Gen III, but $ speak loudly. I'm not saying you are trying to reinvent the wheel...well maybe if Miller Cycle is required, but $ is certainly a driving factor. If your budget is over $50K, you might get into the exotics, but "Miller" probably multliplies that by 2-4X.

Bottom line, IMO: define WHAT you want to achieve, a realistic budget, and see if any one bites. Don't tell them HOW to do it, just ask them to come up with a proposal.

 

Hard to know where to start. Keep in mind that you need to multiply your engine budget by 2-2.5 for a total cost. The supporting parts (fuel system, compressor, exhaust, tranny/driveshaft/rear end, etc. And I'm not sure you will like what you end up with. It won't be like a factory car only faster. It will require constant tweaking.

Rich Krause

 

OldSStroker -


1000hp.
I'm not specifying 1,000 hp as a goal. I'm simply trying to convey that I understand the implications of using parts like this.


No vehicle or performance goals specified.
Actually, I did specify a goal. I was very clear that I want to put some ideas I've been working on into action and see what the result is. I called this an experimental and unconventional engine because that's what it is.


No budget specified.
That's correct. I did not specify a budget. I did not want financials to come into this conversation. Suffice to say that I have the resources to undertake this project, even if I have to spread it out over more than one calendar year.


"Off the shelf" parts prefered.
Yes. The Dart Little Chief, for instance, is an "off the shelf" part, in the sense that it's in the catalogue. So is the GM 6.0 LSx truck block.
I would prefer, as much as possible, to pull already existing parts out of an already existing bin, as opposed to going to a machine shop and having them make some sort of "one-off" custom part for me.
The only truly custom part I should really need to buy is the cam.


Miller Cycle engine desired.
Yes, it is desired. Assuming of course that I can find the answers to my questions. Such as; how far past BDC to hold the intake valve open? What is an appropriate LSA? What sort of static compression ration do I need to achieve the dynamic compression ratio that I want? Is a Centrifugal superchargers boost curve appropriate to a Miller cycle, or do I need some sort of positive displacement blower?


Whew!
Yes. Whew.


Perhaps you might define your goals...
I already have. Twice.


...specify a budget...
That's not the purpose of my post.
Let ME worry about the budget.


...and let the engine gurus go at it.
I don't WANT the "engine gurus" to "go at it"
--> I <-- want to "go at it"
It's my money, my ideas, and if the whole project blows up in my face, it'll be my fault.


Gen I offers many more parts options than Gen III, but $ speak loudly.
THIS is the sort of info I am seeking with this post. Please tell me more.


I'm not saying you are trying to reinvent the wheel...
Actually, that's exactly what I'm trying to do.


If your budget is over $50K, you might get into the exotics
I'm not looking to do anything "exotic"
I believe that I can take a mix of parts that are already "on the shelf", combine them in a slightly different way than is usually done, and come up with a good result. I could also be wrong. That's why they call it "experimenting" And no, I'm not trying to be a wise-***, I am trying to be CLEAR.


Bottom line, IMO: define WHAT you want to achieve, a realistic budget, and see if any one bites.
As I've said, I already have defined what I want to achieve. I'll repeat myself now: I have some ideas that I want to try and in order to try them I will need to actually build the engine.
Also, as I have said, this post is not about money or budget. Let ME worry about that.
Finally, I don't need anyone to "bite". That has nothing to do with what I'm asking.


Don't tell them HOW to do it, just ask them to come up with a proposal.
I'm not seeking a proposal. I am not shopping for bids.

If it helps you to think of it this way, lets just pretend I am building a dyno mule that will never go into any car or run any races.


The problem I am trying to resolve here, in this thread, is this:

I am not very familiar with Gen III family of engines, although I am trying to learn as much as I can.

I am much more familiar with the Gen I family.

I tend to believe that I would be best off using a Dart or Motown iron block, with the nice stuff like priority main oiling, and topping it off with the little chief heads and matching manifold and an off the shelf fuel injection setup.

However, since I don't know very much about what is AVAILABLE in the Gen III aftermarket or what can be DONE with these engines, I worry that I may choose option "A" when option "B" would have been better.

 

I'm not worried about the budget, and I know that I'm not talking about a proven combo that I can just bolt together like a recipe.


You know, I think you guys are overthinking my question.

I took the time to lay out a lot of information because I thought it would make it easier to understand the sort of information I was after. It seems it may have had the opposite effect.

Look, I've been playing around with Gen I engines since the Carter administration, but I have NEVER played with a Gen III engine.

YOU guys have.

That means you're in a better position than I am to compare and contrast the pros and cons of building each type of engine.

Or at least, that was the theory...





This is my fault. I was too long winded in my first post, and what I thought would be helpful turned out to be anything but.

Try it this way:

Compare and contrast the pros and cons of building each type of engine, in the 800-1200 hp range.

 

Look at what has been done already.

The NASCAR boys are getting around 850hp from a 12:1 358cid motor with plenty of restrictions. Just imagine more compression, more cubes, roller cam, etc. Could you pick up 150hp there?

The ProStock guys are getting over 1300hp from a 500cid BBC.

Back when Indy car motors were allowed turbochargers, they were well over 1000hp from VERY small motors.

What do they say that the C5R LeMans motors put out?

I say build a SB2.2 or C5R around 400cid with a single turbo. You should be able to make over 1000hp. Maybe even on pump gas!

 

Don't see anything real tricky to it. Just $³.

Go here..... then go to articles and 1000 HP 383 ci afr 210cc...

http://www.airflowresearch.com/

These kinds of builds are not exactly typical but they certainly aren't anything supernatural either. The Gen3 stuff is still primo $ and Gen1 stuff (the ordinary stuff) is more economical by a long shot. So in my mind, and based on research of my own in this matter, that ends that debate for me.

If this were my build, I'd go with an aftermarket block (Motown, Dart, etc) and I'd build a 421 (3.875 stroke 4.155 bore) or a 4" stroke motor. The Dart Pro1 CNC head (nice price), AFR 227 with a bit of porting or something like these http://www.m2race.com/edelbrockvictor23.htm from M2 should be more than enough to get the job done.
Then you need the boost. Being a larger motor, you won't need as much to make that 1k mark as the smaller 383. May even be able to do it with one large turbo. Of course you'll need as good an intercooler as you can afford and all the other stuff..... and I'm not trying to put the other stuff off lightly cause that stuff (fuel system, computer, etc) is going to be a nice chunk of change in itself. But you already knew that.

To my eyes, the motor part is easy. Don't need no stinkin Miller Cycle stuff or firing order swap cams... just good parts, booost and the green stuff.

-Mindgame

 

Maybe I'm asking too much here, but I do not see the parameters that people generally need to help you meet your goals. On the other hand, you sort of said you don't want us to "go at it"..... so I'm confused about why you even bothered to post. Apparently you are looking for someone to sprinkle holy water on your ideas.

Again, maybe I'm **** here, but what purpose will this engine serve, other than a technical (while unconventional, but using off the shelf parts) tour d' force? Street car? Track car - and what kind of track? Combination of both? What kind of car - 3,600# 4th Gen, 2,200# tube chassis SFI 25.1 car? Is it intended to be used in some sort of "class" racing -- what class? Almost sounds like the goal is simply to build the engine, not to put it in anything.

I know you've defined your goals three or four times in the posts above... but I guess I'm too thick to understand.

 

MG is making it sound easy, which I guess it is given enough cubic money. But Fred's post gets more to the point: easy to do WHAT? Yeah, magazines feature buildups of 1000hp small blocks that run on the dyno. But do you know of any of them actually in any kind of regular use on the street? To the extent that they exist, they are dyno/trailer/garage queens, at least in my experience. There is a reason that there aren't any factory 1000hp street cars at any price. Part of it is emissions laws and the available fuel. But part of it is sheer practicality. Even someone who spends $650,000 on a Ferrari "Enzo" wants to drive it once in a while without a drive along mechanic. Think about the old proverb about being careful what you wish for because you might get it!

Anyway, if money isn't an object I'd do an aluminum big block. No heavier than an iron small block and a lot easier to get 1,000hp from. Forget the blower, just use a really large displacement aluminum big block and a nice set of aluminum heads. Use a 5-speed Lenco with a 3.08 gear, 5th would be a usable OD. A nice custom fuel injection system could make it pretty drivable. Figure ~$65-75,000 total cost if you have someone do it for you.

Rich Krause

 

I just want to elaborate on my budget in case it appears excessive. I assume that this is supposed to be a usable street car, as reliable and safe as reasonably possible and that all the work will be first class. Since it will be as fast as a small plane, I figure it should be built to aircraft standards!

base car $10,000
short block $10,000
valve train $2,500
custom intake $2,500
tranny/bell housing/clutch $10,000 (a built 4L80 or TH400 with GV OD is an option that would save a few $K)
driveshaft/rear end $3,000
fuel injection/engine management/fuel system $4,000
custom exhaust $2,000
chassis $4,000 (custom cage, reinforcements, K-member, etc.)
brakes $1,000
wheels/tires $4,000 (it's gonna need custom wheels to fit huge rubber on the rear)
body work $2,000 (hood, fender flares)
suspension $1,000

So, $54,000 plus the costs to put it all together and sort it out.

Rich

 

Yeah, I have a habit of doing that... especially given unlimited funds. Government employee thing.

True, Lame hasn't been specific enough but with what he has said.... the "WHAT" is not all that ambiguous IMO. It's to build a 1000 hp engine.... can't be a big block.... can be force inducted.

So once we stop pussyfooting around, logic leads us to building a twin turbo small block. It's the most efficient way of making the power and the most expensive... but we aren't worried about the cost.

I would just assume that Bill Gates has become a gearhead and wants to rub Wozniak and Jobs' noses in, "I've got a 1000hp engine and you don't!".

Do I know of any 1000hp small block street cars?

Well, I know of a few that've made 1k with the goal of being street driven.... does that count?
John Meany's Corvette is a good example.... it's a TT small block. That Biscayne Trepanier built is another that got close, again twin turbo small block with 18º heads.

Do I know whether these cars are actually driven on the street? No... nor will I assume that they can't.

Buggati Veyron anyone?

Now we're getting somewhere.... but man that was too easy....

-Mindgame

 

Hey guys exuse my ignorance, but what exactly is this "Miller Cycle" stuff?

The Gen1 parts are proven and more economical as its been mentioned. Personally, I would like to see an LSX motor used as its arguebly the best sbc ever produced. The aluminum block offers weight savings and the rod length is over 6" combined with the stock stroke will get close to your target rod to stroke ratio. AFR has also realeased LSX based heads that so far look really impressive and provide added strength in forced applications.

 

Apparently, I'm not very good at phrasing my questions in a way that gets me the information I am seeking, although I have gotten SOME information that is along the lines I was looking for.


Let me try this one more time, and if I can't get it right, I'll stop bothering you guys.


The Gen I and the Gen III are two different designs, especially in the heads.

In terms of building a high horsepower engine with predominantly "off the shelf" parts, which of those two choices is better and why?

 

That's a better?

Gen I. Why TF.

Rich

 

Make this discussion worth our time.

I can give you the blueprint to a custom 10,000 ft^2 home but it does you little good if it's beyond your reach monetarily. Might be fun to talk about but it isn't wise time management on my part.

So we need a ballpark on your budget. Believe me, it is always an issue.

As far as the discussion so far, there are better choices.

Take care