With all the talk and people thinking it is a necessity to go to 422 I thought I'd throw some insight in.

Here goes some rules of thumbs:

Change to a stroker without changing induction components (cam,headers, heads) then HP peak and TQ RPM peaks will drop.

For example in the ford world, going from 302 to 347 stroker will drop HP peak about 400RPM and tq nearly the same. In the crower cam catalog, it was stated for every 25ci increased by stroke, you drop 200RPM off of HP peak with same components. For every 4 degrees in crease in cam duration (same profile) you raise HP peak 200RPM (rough approximation).

This mean that for a stroker without changing anything else, you will not get proportionate POWER increases to increase in cubic inches.

On the 422 strokers on this side, I see many of them putting out "poor" TQ numbers for such a large cubic inch. We see 460, 470rwtq on many of the Hydro cammed setups with good CR.

Good build 346's are putting down 390, 400 rwtq. A good built 422 should put over 500rwtq on a hydro cam.

On a side note, the all bore's 382-388's are putting down 450-460rwtq With similar power numbers.

With the good built 388 putting close numbers down, why do the 422?

WIth the 388 we get good rod ratio, lower piston accelerations from TDC (don't need as much head flow). However the engine RPM of the HP and TQ will be higher than the 422. But who cares? The big deal is the piston speeds. The avg piston speed of the 388 is going to be less than the 422 meaning lower wear and tear on the internals.

Just some thoughts.

The price/performance ratio of the 388 looks very good. :hat

 

Intresting...

 

Exactly what I've been preaching bro. Faster revving, faster developing HP. :) Thanks for the post.

The ultimate would be a 388 all bore, LS6 Stage II -III Heads Matching cam, all the bolt ons, and programming. Oh man :)

Then the total ultimate to take advantage of the relaible stroke in an all bore, is a 2001+ 6.0 liter LS6 casted truck head (for less compression), and go with an ARE Twin Turbo on a 388 all bore.

Here is nineballs MTI first off (from a long time ago) experiemental 382 all bore with a T1 cam and NO PROGRAMMING. These motors can be built for under 10 Grand. Nineball is running 11.1x times at 125+ N/A

Look at that stock stroke big fat torque curve too...







[Modified by kewlbrz, 11:14 AM 11/26/2001]

 

A lot of this is true, but you are making asumumptions that most just would not do. If you are going to go with a 422, you are most likely going to do additional porting on the heads, increase cam size, etc.

In the end, more cubes = more power. There is no replacement for displacement!
I have never seen a motor in any class be smaller than the the limit by more than a half a cubic inch! That ought to tell you something. :)

With all that being said, 422's loose some efficiencies of a smaller motor and for that reason, the big cubic inch motors might not be the right way to go.
As for the lower torque numbers out of the 422, a lot of that might have to do with cam selection, heads, etc. Who knows. ;)

 

Now if I can just dig up the final cash to pay off my 388 and get it in the car!! :p:

With the lower piston speed of an AB with a stock crank & also NOT having increased side loading, would you think the larger 4.125" re-sleeved bore would be safer in an AB setup than in a stroked 42x setup?

Some worry about the 4.125" re-sleeved bore.

Hoping for some good numbers when I finally get her in. Some minor cam tweaks, S3 head tweaks, C/R & Timing tweaks.

Btw.. Where do you think I'll see the power peak on this setup? Does an AB peak & hold at higher RPM, or does the Stroker? Which falls off first? Do you think I'll want to shift high? I'd prefer a higher 6.6k or so shift-point, but am not sure where the powerband will end up.


[Modified by MelloYellow, 1:05 PM 11/26/2001]

 

In a pure form no, but there are many considerations such as reliability, cost, etc. Displacement is not always the final measure of being able to perform. Quick revving for quarter mile performance in a destroked or all bore situation can outperform a equally equipped larger displacment motor.

There are many more dynamics then just displacement.

A built 427 Big block will stomp say a 432ci LS1 small block.

Again, just pointing out that displacment is not the final say in performance.

 

There is only so far the LS1 heads can go.

The 422 do not make enough more power vs the 388 to warrant the cost differential.

With the 422 you increase the cubes at expense of cyllinder wall loading and shorter piston. This will result in decreased engine life.

The 388 will probably be more friendly with the LS6 intake and smaller tube headers.

 

I definitly agree that there are different ways to get displacement and better ways to get displacement. I also agree that the 422 is not the right answer for most of the people that are getting them. There are many more considerations to take in than what is listed here. I am very familiar with them. :) I still say that in an all out HP race, there is no replacement for displacement. :)

As for the LS1 heads only being able to be taken so far... we have not found the limit yet! When that limit is found, send them off to the welders, raise the runner, and start redisigning the heads! Now you have a whole new limit to contend with. ;)

I think we are pretty much in agreement here, I just might not have stated my point clear enough. :blueangel:

 

HP is simply a derivative of of torque. If you talk to most engine builders the advice you will be given is to build a motor to make torque, and HP will take care of itself.

Most of the examples stated before are correct. If you decrease displacement, then RPM must go up to realize the HP you are trying to obtain. If you increase dispalcement, then the RPM that X hp will be realized will become lower.

But, if I build a bigger motor heads, camshaft, and intake must get bigger to support the additional airflow. Now one of the problems in the ls1/ls6 is that there are some bottlenecks in the motor espcially in the intake. This appears to be one of the reasons that many of the big cube motors don't seem to make the numbers folks think they should.

A small example. Put a Comp 292H cam in a 327 and it sounds crazy. Put the same cam in a 406 or a 434 and it sounds much milder. The same goes for a B303 or a X cam in a 302 vs a 347 or a 408.

The rule still applies that there is no replacement for displacement.

 

And RPM.


The engines in Diesel locomotive trains are V16's with intake valves about a foot and a half long. They make about 5000 HP and redline at about 900 RPM.

It takes forever to get that bad boy just to redline. Thats a hell of a lot of weight to be thrown around.

In the real world this extreme example of displacement would not be conducive to quarter mile performance. Even not considering how much the engine weighs.

As a side note: these massive engines simply turn electric motors which inturn, turn the wheels. The windings of the electric generator is so large you can walk through it.




[Modified by kewlbrz, 4:43 PM 11/26/2001]

 

Very good points that go back to the basic dynamics of engines. Just so I understand; the 382 is a stroke change only. The 388 is a stock crank with a larger bore?? If so the cost associated with building one is new pistons, new sleeves and some expensive machine work. Is this a true statement?

I am looking for another "resonable" upgrade above and beyond the head/cam setup I currently have. The 422 is a expensive endevour.I thought that the stroked method would yield a decent increase if properly combined with a well ported set of LS6 (or for that matter a set of ported LS1 heads) and a carefully thought out camshaft without breaking the bank.

I guess a lot of people feel that bigger is always better, but those who understand the meaning of piston speeds and rod ratio will make sense of this post.

Great insight!!
:)

 

Here is a little info for you regarding flow, and various heads/intake combos.

<BLOCKQUOTE>code:<HR><PRE>Without Manifolds - Headflow Only:

Cylinder Head Intake Manifold .200" .300" .350" .400" .450" .500" .550" .600"

Stock LS1 N/A 137 187 207 223 228 237 242 243
Stock LS6 N/A 156 204 225 243 257 268 275 278
Ported LS1* N/A 144 200 225 245 261 272 283 292
Ported LS1** N/A 164 217 234 253 270 284 296 305
Ported LS6 N/A 159 212 236 255 272 300 307 314


With Manifolds:

Cylinder Head Intake Manifold .200" .300" .350" .400" .450" .500" .550" .600"
Stock LS1 LS1 136 184 200 214 222 227 229 235
Stock LS1 LS6 136 186 206 223 227 236 241 242
Stock LS6 LS1 156 199 212 224 232 238 243 247
Stock LS6 LS6 154 204 220 235 247 257 263 265
Ported LS1** LS1 141 185 205 222 232 241 251 258
Ported LS1** Truck 163 206 224 237 249 262 265 270
Ported LS1** LS6 166 211 229 244 257 269 277 283
Ported LS6 LS1 156 199 217 230 242 253 263 268
Ported LS6 LS6 153 202 222 241 257 270 280 289</PRE>[/QUOTE]

* Original Stage II heads from New Dog, Old Tricks; GMHTP May/July 2000

** Latest revision.

Info originally from Chris Endres




[Modified by kewlbrz, 5:23 PM 11/26/2001]

 

When you look at those head flow #'s it seems as if the LS6 head only really show's any decent increases over the ported LS1 heads over .600" lift. I would think that the LS6 ported head would only provide a sizable gain with a high strung stroker or AB motor that was using a camshaft in the .580" to .640 lift range.

What's the deal with the 388 motor? Is it just a bore increase with the stock stroke? If so ,how does it differ in overall power output vs. the "stroked" 328?

Thanks

 

Those flow number are VERY neat to look at huh.

To answer your question:

The stock bore and stroke is:

3.90 x 3.62
This gives: 3.90^2 x 3.62 x .7854 x 8cyl = 345.95ci displacment

Looking at a stock bore stroker:

If you use stock bore and a 4 inch stroke:
3.90 x 4.00
This gives: 3.90^2 x 4.00 x .7854 x 8cyl = 382.26ci displacement

Looking at all bore only with stock stroke:

4.10 x 3.62
This gives: 4.10^2 x 3.62 x .7854 x 8cyl = 382.34ci displacement

4.125 x 3.62
This gives: 4.10^2 x 3.62 x .7854 x 8cyl = 387.02ci displacement

Strokers are better for torque and doing a lot of work over time.

All Bores are better for rapid power development, and doing work over less time.

A great bennefit of an all bore over a stroker is that you unshroud the valves and create excellent flow, coupled with quicker developing RPMs, and much greater stability in side wall loads and reciprocating weight.

 

The majority of these engines have the same heads and cams as 2FST4U has already alluded to so you can't expect hp to be way different. SW's motor is stronger than any 382s and so is ours as is a few others that had matching cams and heads suited to the large engines. Ask the Colonel if he's going to drop back to a 382.
:smash:


[Modified by RACER7088, 4:14 AM 11/27/2001]

 

Here goes my rule of thumb:

Bigger always wins. Bigger is always more streetable. Bigger is always more raceable. The only way your gonna go faster with less is if you can take off weight. We can all take off the same weight on the street. The fastest cars on this board and others are the big engined ones. Bigger always wins.

The end. :nono:

 

Your "rule of thumb" is your opinion...

I dont think anyone will dispute, in the "GEN III" motor world, that a super stroker is the ultimate.

However the fact still remains that when you take the whole dynamics of a motor into account, a larger displacement motor can have disadvantages over a smaller displacement motor with respect to performing in the quarter mile.

The best bang for buck BY FAR still is an all bore.

 

This is 100% true! Best bang for the buck, YES! Best overall, no.
I am right there with Eric. Bigger will always win! There are different ways to get more displacement, but bigger always wins! :)

the best bang for the buck is actually just heads and cam. You might want to change the rods and pistons, but the rest of the setup is good to go for the street. With the right combo, 120+ MPH on stock tires is not too large of a task. If at that point, you decide that this is just not enough, then go with a bigger engine and additional ports with a matching camshaft.

PS The LS6 intake is AWESOME! I really do not think that it is holding the big motors back as much as some people think. Isn't a stock LS6 intake on the SAM racing camaro turning somewhere around 7800 RPM and making mega power?!?! Doesn't seem like it is too much of a bottle neck. ;)

 

kewlbrz; your right! but only on the dyno. On the track (Straight or Curves) cubes win,, even with a slight HP disadvantage. I know of several cars on this forum that make more rwhp than mine but don't et or mph close to my car.. Why is that??

:seeya

 

Actually I meant soley on the track. I know what power under the curve is compared to peak power. However the other factor is quick revving, and no TDC, or BDC piston lag as in a stroker.

I still contend that a engine, like an all bore can outperform an engine of equal or somewhat larger displacement which acheives it equal or somewhat larger displacement by stroking rather than boring. Obviously not an engine that utilizes both principles as in the current super strokers.

For under 10K an all bore is a sweet reliable engine. Several 388's ( i dont know of any in C5's yet) all bores are being built and put in C5's as we speak. It will be very interesting to see these perform.


[Modified by kewlbrz, 11:28 PM 11/26/2001]