BIG Turbo build planned - turbo guys!

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zac_F71

zac_F71

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Well guys the plan is slated - just made the last parts orders for my fox bodies SO time to gather some info on turbo'ing the 225 in my 71 Demon..

Planned -
rebuilt 225 - decked milled .010" to clean it
7.5-8.5 static compression
ported head, bigger valves, hardened seats, stiff valve springs, deck milled .010" to clean it
ARP bolts/studs through out motor
double roller timing chain
more than likely get a custom Comp solid cam for a turbo in the .450" lift range
Offy 4bbl intake
FAST EZ EFI
Spectre blower hat
MP70 or similar turbo
mild steel custom turbo mani made from 1/2" eBay flanges, Headman 3-1 collectors and a SBC DIY 1 5/8" header kit
3" down pipe, 3" mid pipe, 3" Dynomax Ultraflow, 3" Summit tail pipe, and a eBay 3" A body exhaust tip (all single (IE no single to dual piping) and driver side location)
larger intercooler (haven't picked one yet)
rebuilt A904 to handle the better part of 600hp
stock rebuilt 8 3/4 w/ 3.23 gears
Weld Prostars and 275/60 Nitto drag radials
build the chassis to handle the power and remain a street car that can drive anywhere


My many questions are -

1. can you bolt a slant 6 to a small block K member? - I'm wanting to run the QA1 tubular K member setup for a SB...

2. has anyone run a FAST EZ 4bbl EFI on a slant 6?

3. what are the power limits on the stock slant crank, block, and K1 aluminum rods? I want to run 25+psi and make north of 550hp at the crank

4. is there SFI spec flex plates, and stall converters available? Which to get?

No parts have been bought yet except the exhaust flanges - need to sell a few things and finish my fox bodies before starting this hands on and updating my build thread in the resto section...
 
Ok you need to check ALL oil passeges when running the ARP studs in the bottom end, they can block holes!

stock crank-fine

Block- will be in good shape with the studs, though i would look into billet 440 caps and maybe even a girdle

Aluminum rods- work yes, good idea? no, they have a short service life, run the K1 steel rods

Comp cam- no, they nitride the cams which eats oil pump gears, unless your running an external belt pump, OCG oregon cam grind is the way to go

cut the mounts off the SB K and make your own, done deal

fast works on everything, Darter6 used one
 
SFI flexplate- take a neutral balance SB wheel and offset one hole, done

Converter- EDGE RACING, talk to Andre, he is the man
 
Just a FYI. If you don't have an engine yet, make sure you get a 68-75 engine. Has forged crank with a large crank register. It is possible to use a 76 up cast crank engine, but I don't know how much power they can handle. The first 10 sec door slammer slant did use a cast crank. The crank is lighter, and K-1/Molner rods are available for the cast crank.
 
Thinking outside the box here, get the hemidenny k-member so you can use off the shelf OEM parts and he will set it up for any engine you please.
 
The engine slated is my Demon's original 71 225.. has 90k-ish miles and probably don't need a rebuild BUT it's going to get it.. Thanks 805!!
 
Sounds like a cool build, i seen a 225 turbo before it was sweet
 
on 25 psi your going to want to run the weisco pistons or some other custom piston. the weisco pistons were built to be used with the K1 rods
 
Piston to valve/bore to valve clearance may be an issue especially if you go oversize. I'm sure you can find plenty of k1/weisco builds to get an idea.

Sounds like an awesome build can't wait to see it.
 
adiffrentcity said:
Piston to valve/bore to valve clearance may be an issue especially if you go oversize. I'm sure you can find plenty of k1/weisco builds to get an idea.

Sounds like an awesome build can't wait to see it.
Click to expand...

Mark has his .015 in the hole and it clears .550 lift, only grinding on the piston was due to .030 offset pins
 
adiffrentcity said:
Piston to valve/bore to valve clearance may be an issue especially if you go oversize. I'm sure you can find plenty of k1/weisco builds to get an idea.

Sounds like an awesome build can't wait to see it.
Click to expand...

I think you're going to have more fun than the Law allows with this thing!

The first thing you probably should buy is a data-logging, wideband, O-2 meter to check your air-fuel ratio, keeping in mind that too much compression, too much spark advance, too lean a mixture, and insufficient octane can all cause engine-destroying detonation which can ruin an engine in the twinkling of an eye.

You probably already know all of that, but the mixture is the easiest to get wrong, of this assortment of evils, and bears watching like a HAWK!

I think you're on the right track here, and the guys who populate this board can give you some really good advice.

I think you've come to the right place! :)

Welcome aboard!:cheers:
 
25 psi, wow cant wait to see this build! Are you sure .010 cut will keep you in the 7.5-8.5 range? Cometic or copper head gasket!
 
pishta said:
25 psi, wow cant wait to see this build! Are you sure .010 cut will keep you in the 7.5-8.5 range? Cometic or copper head gasket!
Click to expand...

some guys are making coated copper gaskets for us now... just can think if the name
 
Sure can.....
"The Only Streetable Aluminum Rod
Urban legends abound in the gearhead community. One is: aluminum connecting rods don't work in street engines. Prior to the mid-'70s, that might have been true, however, introduction of the Bill Miller Engineering Forged Aluminum Connecting Rod in 1975 discredited that myth.

The BME Rod has great durability in high-end, high-power, street/strip or hot street engines because it is die-forged, rather than cut out of a plate. Bill Miller Engineering's unique, aluminum alloy further enhances fatigue strength such that the durability of BME Rod rivals that of many forged steel rods and exceeds that of a few.

About 25 years ago, a few resourceful engine builders, led by H-O Racing's, Ken Crocie, began using BME Rods in very-high-performance street engines. Crocie, a racing and street/strip Pontiac V8 specialist, faced with a shortage of acceptable steel rods for Pontiac V8s, began to use BME Aluminum Rods in some engine builds. While, since then, other engine builders followed Crocie's lead, admittedly, use of the Bill MIller Engineering Rod in street engines has not been widespread–but that's only because of the stubborn belief that any aluminum rod is unsuitable for street use.



"In a hot street application, using the aluminum rod is a no brainer," BME President, Bill Miller, said in an interview with an automotive magazine. "I don't know how the myth that aluminum rods can't be used on the street got started, but I'll guess that, back in the 60s and early-70s, they weren't making them using the process we're using today. With the material we've got and they way we manufacture the connecting rods, they'll live a couple hundred thousand miles on the street because a street application is, for the most part, low load. Our basic Aluminum Rod is made for an 1000-hp, 10,000 rpm race engine. The design criteria for the connecting rod is way overkill for what it's going see on the street. We been running aluminum rods on the street for more than two decades."

Why build a street engine with BME Rods? One reason is the "cool factor." Bill Miller Engineering Rods are unique, high-end racing parts and there always will be people who spend extra money to have the same rods in their engines as John Force puts in his. More importantly, there are practical reasons for using BME Rods—the same reasons racers use them: less reciprocating and rotating mass due to their comparative lightness. That allows the engine to accelerate quicker. Lighter rods also improve throttle response and allow the engine to run reliably at a higher rpm than it could with steel rods.


You do a few things differently when setting-up a street engine for BME Rods. Minimum bearing clearance at room temperature should be .002-.0025-in. Wrist pin clearance should be .0006-.0008-in. Rod side clearance should be .020-in. The engine's oiling system needs to be appropriate for a racing application with larger rod bearing clearances once the oil reaches operating temperature. The oiling system must be configured to provide 10 psi, hot oil pressure for every 1000 rpm in the engine's rpm range. The minimum acceptable oil is a premium, 10W30 synthetic and Bill Miller Engineering recommends either Red Line 10W30 Engine Oil or Gibbs Driven HR 10W30 Oil. Engines with BME Aluminum Rods must not be run at high load or high rpm until oil temperature reaches at least 130 deg. F. Lastly, while Red Line and Driven oils lubricate reliably at oil temperatures up to 300 deg. F, the recommended oil temperature for an engine using BME Rods is 200 deg. F.



Standard BME Forged Aluminum Connecting Rods for most production Chevrolet, Chrysler and Pontiac V8s are reliable replacements for steel rods in engines of up to 1000 horsepower. Aluminum Rods for some Ford V8s of similar power output are available on special order. A Big-Block Chevrolet style, Pro Stock rod, good to 1200-hp, is, also, available. If the application is a Chrysler 426 Hemi or big-block "wedge", BME's blown-alcohol rods can be used at levels well over 2000-hp with outstanding reliability/durability"....

Don't argue with me if you don't agree....argue with http://www.bmeltd.com/rods.htm
 
Longevity has been then only downfall ive heard of (stretch due to heat cycles). I'll have to give them a call and pick their brain.
 
At 25 psi, you ARE expecting to use a custom fuel mix, right? 8.5:1 CR will be marginal for those pressures, so I would go easy on milling anything, just get it straight, you can always take off more later if you plan ahead.

Why bother much with the porting, etc.? That is what the turbo is for. Just the larger valves are of value, IMO.

I have no idea if that engine will take that level and live for long.
 
nm9stheham said:
Why bother much with the porting, etc.? That is what the turbo is for. Just the larger valves are of value, IMO.
Click to expand...

Out of curiosity, why would you hold one important and not the other? Personally, I would do both the porting and the large valves, because in my mind, least resistance is better most always. i would just think it to be less work for the turbo to have to do, letting you make more power per psi of boost. Keep in mind, that is just my opinion.
 
It is just that the porting does not do a whole lot on most engines for airflow when you are putting any significant level of boost on the intake. You are not struggling to increase airflow within the limit of just 14.7 psi of maximum atmosperic pressure like in a normally aspirated engine; you can step up boost pressure with the right turbo to 2 to 3 times normal atmosperic pressure and overcome a lot of restriction; in that way, turbos are easy.

You can push 80 HP per cylinder of boosted airflow through most stock heads and more through some like a good hemi head; 2-2.5 HP per CI is easy to get with all sorts of engines if you can make it live. The turbo system airflow is mainly set by the smallest restrictions, which is the throttle plate (obviously I guess!) and then the turbo impeller. Valves are down the line in importance (which is partly related to the fact that turbo cams are not nearly as open as normally aspirated cams) and then porting at/near the bottom of the list. You'll get more from a free flowing exhaust which helps the exhaust side restriction, and as large an intercooler as you can get, which keeps the charge cooler and compressed and the density up. Impeller design will have a lot to do with off-idle response; the guys that make these all day long have a lot of tricks.

For 500 HP, maybe the porting on THIS head is needed..... but for a 225 ci, 6 cylinder, it would not normally be needed with enough boost pressure. I would try it without first unless someone has already established the need, and focus on keeping the thing alive at 300-350 HP and then work my way up in pressure. For 500 HP, I think (know) there are a lot more thing that will need attention than the porting.

And, OBTW, on the AL rods.....steel (and some irons) have a property that aluminum does not possess. If the distortion/load is kept below a certain level, steel can be loaded and unloaded an infinite amount of times; it never has a life limit. Aluminun never can do that; there is always a finite number of load cycles on any Al part. You can increase the number of Al load cycles but never make it infinite. So there is some truth in the limited life of Al rods. It probably has been made better by BME, but there is no such thing as infinite load cycle Al. (Otherwise perfectly good airplanes are retired after so many flight hours due to this factor.) Hence, the article cited is likely truthful in saying the rods will live on the street for a couple hundred kmiles. In a 500 HP slant 6, however, the loads are going to be pretty high. I kinda epxect the OP to be leaning on this engine....a LOT.
 
Thanks for taking the time to post this info, very interesting/informative to me.
 
Brandon Weaver said:
Out of curiosity, why would you hold one important and not the other? Personally, I would do both the porting and the large valves, because in my mind, least resistance is better most always. i would just think it to be less work for the turbo to have to do, letting you make more power per psi of boost. Keep in mind, that is just my opinion.
Click to expand...

Fitting larger valves to a cylinder head is, if the desired larger valve is the correct-length, with the same stem-diameter, and valve spring installed-height is the same as the originals, a slam-dunk to accomplish. Porting a slant six head is a time-consuming, expensive process, fraught with the possibility of hitting water, something that is not easy to repair.

I have heard prices that range upwards of $1,500.00 for a ported head, complete. Simply putting the oversize valves in, doing some "pocket-porting" in the valve bowl area and letting a couple of more pounds of boost make up for the flow restrictions of the un-ported casting could save upwards of $1,000.00 if porting is not utilized in the "build."

Unless the engine is to be a balls-to-the-wall, all-out, NHRA Competition Eliminator effort where every HP counts, it seems to me that it makes $$$$ sense to allow the turbo to make up the slack by adding some extra boost in lieu of spending another grand on porting.

Just my 2-cents... :happy7:
 
nm9stheham said:
And, OBTW, on the AL rods.....steel (and some irons) have a property that aluminum does not possess. If the distortion/load is kept below a certain level, steel can be loaded and unloaded an infinite amount of times; it never has a life limit. Aluminun never can do that; there is always a finite number of load cycles on any Al part. You can increase the number of Al load cycles but never make it infinite. So there is some truth in the limited life of Al rods. It probably has been made better by BME, but there is no such thing as infinite load cycle Al. (Otherwise perfectly good airplanes are retired after so many flight hours due to this factor.) Hence, the article cited is likely truthful in saying the rods will live on the street for a couple hundred kmiles. In a 500 HP slant 6, however, the loads are going to be pretty high. I kinda epxect the OP to be leaning on this engine....a LOT.
Click to expand...

The fact is, the really successful turbocharged 225's such as Ryan Peterson's '66 Valiant and Tom Wolfe's '70 Dart, make their horsepower (arguably 500+) without ever exceeding 5,500 rpm, so the early red-line goes a long way toward negating the advantage of lighter rods (aluminum.) At the boost-levels they utilize (25-pounds, plus,) the difference in the aluminum rods' reciprocating weight's effect might be minimal.

At nearly $1,000.00 a set of 6 for custom aluminum rod forgings, the K-1, forged steel rods with their matched Wiseco forged pistons at virtually the same expenditure for BOTH, makes a lot of sense to me. It's like you're getting the pistons for free...


Food for thought...
 
And to add to the above.....the rotational inertia of the torque conveter and trannie parts is far higher than any inertia contributed by the rods. So, IMO, the rod inertia is even more down in the noise at the above mentioned RPM ranges. The Al rods could take some load off the crank but again, the RPM's are relatively low; I think your thinking is sound.

Interesting that the RPM stays low in the above examples; that says to me that there IS a flow restriction in addition to the turbo somewhere in the system. I say this because turbo rally cars have been running 35 mm restrictors worldwide for the last 10 years or so, and the RPM's typically flatten out in the 5000-6000 range with the restrictors. Of course, the big boys have figured out how to get around that with different turbos and tuning and fuel mixes. Those 2 to 2.5L 4 cylinder engines put out more usable torque and HP now than without the restictors 10 years ago; they are in the range of 400+ peak HP with a 35 mm diameter restrictor right in front of the turbo...so that shoudl give you some idea how much you can work around any head porting restrictions.
 
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