Advanced Engineering Tech - idea for EMC motor,destroked 6.0

tossing around the idea of entering a motor in the Engine Masters Challenge(assuming they would accept my application).obviously i don't have aspirations of winning or even coming close. goal would be to have an awesome experience and at least have a respectable score for a low buck effort.
anyway,my idea was to put a 4.8 crank into a .030 over iron 6.0 block,with 243 heads.nothing fancy,just good machine work,and a cam spec'd to the required RPM range.
my thinking on this is the 243s should have enough airflow to support 330ci,and the bigger bore to help unshroud the valves.
is my thinking flawed?anybody try something like this?
remember,not trying for an all out effort.i know ported heads/lightweight components would be ideal but not what i'm after.

I've noticed that the better EMC entries tend to have more "shrouded" valves than what one would expect. One thing the EMC has been great at is debunking conventional wisdom towards how to build high performance engines.

I've noticed that the better EMC entries tend to have more "shrouded" valves than what one would expect. One thing the EMC has been great at is debunking conventional wisdom towards how to build high performance engines.yep,ive seen that.i thought the biggest reason was to help control detonation.at least that's the explanation given.
looking at the entries you see a lot of different combos.
or i could just build a 6.0,would probably be cheaper yet.

yep,ive seen that.i thought the biggest reason was to help control detonation.at least that's the explanation given.
looking at the entries you see a lot of different combos.
or i could just build a 6.0,would probably be cheaper yet.

I hear rumors of doing separate classes in the future. One for the ballers and one for the budget guys, so you never know. I like that idea since it seems like the same 10 builders win every year, and this may encourage more of the average joe's to participate since we won't be up against the likes of BES, Kaase, and SAM.

I hear rumors of doing separate classes in the future. One for the ballers and one for the budget guys, so you never know. I like that idea since it seems like the same 10 builders win every year, and this may encourage more of the average joe's to participate since we won't be up against the likes of BES, Kaase, and SAM. actually they have that this year.that's what made me think about trying to enter.
a few years ago a guy built a 305 pulled from his back yard.used a basic rebuild kit and honed the cylinders with a block of wood and sandpaper,lol..
made just under 400hp!

I think two turbos would help. :)

actually they have that this year.that's what made me think about trying to enter.
a few years ago a guy built a 305 pulled from his back yard.used a basic rebuild kit and honed the cylinders with a block of wood and sandpaper,lol..
made just under 400hp!

Thats scary, lol.

Yeah this setup would be great with two turbos as well, but the more important issue is going to be an oil pump to support the high rpms as well the valve train, I threw this motor into a program at school (DynoSim5) and it worked out well with boost BMEP was in the 5-600 PSI range and MPS was around 4800 fps. This was on twin t88 turbos and about 14 lbs of boost. The motor reved to like ~9k rpms.

I would love to see how it works out for you, I want to do this as well.

Yeah this setup would be great with two turbos as well, but the more important issue is going to be an oil pump to support the high rpms as well the valve train, I threw this motor into a program at school (DynoSim5) and it worked out well with boost BMEP was in the 5-600 PSI range and MPS was around 4800 fps. This was on twin t88 turbos and about 14 lbs of boost. The motor reved to like ~9k rpms.

I would love to see how it works out for you, I want to do this as well.

The EMC only pulls to 6700RPM and turbos are prohibited. It's mostly about overall horsepower and torque per cubic inch, and I'm not so sure a destroked LQ4 is going to do the trick. At least, there really doesn't seem to be a real advantage to it. Similar ideas have been tried already.

yeah,no turbos in the EMC..
if you look at the top 10 finishers for 2010,3 of them had big bore/short stroke combos..
the 7th place finish of the Power Shop Racing SBC had a whopping 307ci,with a 4.030 bore/3.0 stroke.
338ft.lbs at 2500rpm,with a peak of 417ft.lbs at 4700rpm is pretty good for that small of displacement..
it's not that i think there is an advantage to a short stroke/big bore combo.it's about feeding enough air to support the engine your building.IMO,it's cheaper to make HP per CI on a smaller motor.i have a set of 243s laying around in my garage. untouched they will flow enough air to support 330 cubes.
plus the biggest advantage is i can get the rest of the parts for dirt cheap,lol.

I would think you would have better luck since its rpm limited with a 4.8/5.3 stroker myself, with a ton of compression

yeah,no turbos in the EMC..
if you look at the top 10 finishers for 2010,3 of them had big bore/short stroke combos..
the 7th place finish of the Power Shop Racing SBC had a whopping 307ci,with a 4.030 bore/3.0 stroke.
338ft.lbs at 2500rpm,with a peak of 417ft.lbs at 4700rpm is pretty good for that small of displacement..
it's not that i think there is an advantage to a short stroke/big bore combo.it's about feeding enough air to support the engine your building.IMO,it's cheaper to make HP per CI on a smaller motor.i have a set of 243s laying around in my garage. untouched they will flow enough air to support 330 cubes.
plus the biggest advantage is i can get the rest of the parts for dirt cheap,lol.

I agree for the most part, but as far as the competiton goes, I think the more important question to ask is will the heads feed the engine where you want it to? The 243/799 castings supported the 364ci LS2 in an RPM range similar to the EMC RPM range, and heavily worked over, have supported 427ci engines to 9600RPM. Sure they'll support a 330ci engine, but at what RPM? I would be worried that the power would come in too late in the RPM range to score points in the EMC.

I agree for the most part, but as far as the competiton goes, I think the more important question to ask is will the heads feed the engine where you want it to? The 243/799 castings supported the 364ci LS2 in an RPM range similar to the EMC RPM range, and heavily worked over, have supported 427ci engines to 9600RPM. Sure they'll support a 330ci engine, but at what RPM? I would be worried that the power would come in too late in the RPM range to score points in the EMC.i see your point.
but for the most part,the intake and cam will determine the rpm range the motor will make power.
at 210cc intake port volume with the stock valves i don't see a problem making power in the 2500-6500 range as long as it's cammed properly,and of course the right intake is used.(hell,i will probably just use the truck intake!)i would bet you the smaller cube EMC motors ran bigger intake ports then the 243s.
keep in mind the 799/243s are used stock on the later 5.3 truck motors.
like i said,i don't expect to win or even come close,just a respectable finish with the parts i have on hand.

I would think you would have better luck since its rpm limited with a 4.8/5.3 stroker myself, with a ton of compressionthe street class is limited to 11.5:1 CR.and i would use every bit of it.of course that is for this years challenge,next year might be different..

tossing around the idea of entering a motor in the Engine Masters Challenge(assuming they would accept my application).obviously i don't have aspirations of winning or even coming close. goal would be to have an awesome experience and at least have a respectable score for a low buck effort.
anyway,my idea was to put a 4.8 crank into a .030 over iron 6.0 block,with 243 heads.nothing fancy,just good machine work,and a cam spec'd to the required RPM range.
my thinking on this is the 243s should have enough airflow to support 330ci,and the bigger bore to help unshroud the valves.
is my thinking flawed?anybody try something like this?
remember,not trying for an all out effort.i know ported heads/lightweight components would be ideal but not what i'm after.

I would use a 3.90 bore (LS1) and the 4.8 crank for about 313 inches. That is not far from the dimensions of the LS engined Daytona Prototypes (DP). Since block weight is no penalty for a dyno "mule", start with a recycled 4.8 truck engine. The iron block has the same bore as the 5.3 and can be safely bored to 3.90. You can also us some very nice shelf Mahle pistons, or relatively inexpensive slightly specials. Upgraded rod bolts in stock 4.8 rods will be more than sufficient. At the relatively slow acceleration rate used in the EMC, lightweight rotating/reciprocating parts are not a good bang for the buck.

Heads will be the most important issue by far. Ported 243s with stock size valves were used on the DP engines. The latest ones used the FAST LSXRT intake (146602). The 90mm truck intake is a close second and might even be better for the 6500 max speed and it is a ton cheaper. DP engines used the fugly truck intake until the FAST was approved and they went to 7100.

Done correctly, the engine described above could be a contender for the EMC Street Division class win. You would need the correctly ported heads, the correct valvetrain (which could be HR, very lightweight and affordable), and absolutely the correct tuner for the EFI engine. All of those things/people exist, and they are not involved in the EMC as far as I know.

Second point: if a 4.00+ bore was considered (330 or so cubes), you could do better with L92 heads. I suggest that about 98-99% of the folks who read that would either strongly disagree or laugh. Talking with the other 1-2% might prove instructive.

FWIW, it's probably way too late to apply for the 2011 EMC...unless they didn't get much response in the Street Division. I haven't checked recently.

My highly-opinionated $.02


Jon

I would use a 3.90 bore (LS1) and the 4.8 crank for about 313 inches. That is not far from the dimensions of the LS engined Daytona Prototypes (DP). Since block weight is no penalty for a dyno "mule", start with a recycled 4.8 truck engine. The iron block has the same bore as the 5.3 and can be safely bored to 3.90. You can also us some very nice shelf Mahle pistons, or relatively inexpensive slightly specials. Upgraded rod bolts in stock 4.8 rods will be more than sufficient. At the relatively slow acceleration rate used in the EMC, lightweight rotating/reciprocating parts are not a good bang for the buck.

Heads will be the most important issue by far. Ported 243s with stock size valves were used on the DP engines. The latest ones used the FAST LSXRT intake (146602). The 90mm truck intake is a close second and might even be better for the 6500 max speed and it is a ton cheaper. DP engines used the fugly truck intake until the FAST was approved and they went to 7100.

Done correctly, the engine described above could be a contender for the EMC Street Division class win. You would need the correctly ported heads, the correct valvetrain (which could be HR, very lightweight and affordable), and absolutely the correct tuner for the EFI engine. All of those things/people exist, and they are not involved in the EMC as far as I know.

Second point: if a 4.00+ bore was considered (330 or so cubes), you could do better with L92 heads. I suggest that about 98-99% of the folks who read that would either strongly disagree or laugh. Talking with the other 1-2% might prove instructive.

FWIW, it's probably way too late to apply for the 2011 EMC...unless they didn't get much response in the Street Division. I haven't checked recently.

My highly-opinionated $.02


Jonyep,too late for this year.all applications are filled,and the deadline for mailing was the 15th.this would be for next year.
thanks for the advise Jon,i appreciate it.now that you mention it,i was tossing the idea around of using L92s,and i have a small cam that might actually work with those heads on a small cube motor.216/224 112+3 lsa.although probably a little small and i think it would peak a little too early.(maybe if i install it at 112+0?)
i have some parts laying around and not a lot of money.just thinking if i do this,making the most of what i have on hand.and the tuner would be me,so not a lot of help there!lol
but now you got me thinking!

yep,too late for this year.all applications are filled,and the deadline for mailing was the 15th.this would be for next year.

but now you got me thinking!


That was the plan!

Jon

FWIW, a 313 that had a fat torque curve and made 530 hp @6500 would be in the running.

Don't think that would happen with my budget,lol.I was hoping for around 450 or so with a fat TQ curve.

I would use a 3.90 bore (LS1) and the 4.8 crank for about 313 inches. That is not far from the dimensions of the LS engined Daytona Prototypes (DP). Since block weight is no penalty for a dyno "mule", start with a recycled 4.8 truck engine. At the relatively slow acceleration rate used in the EMC, lightweight rotating/reciprocating parts are not a good bang for the buck.

Heads will be the most important issue by far. Ported 243s with stock size valves were used on the DP engines. The latest ones used the FAST LSXRT intake (146602). The 90mm truck intake is a close second and might even be better for the 6500 max speed and it is a ton cheaper. DP engines used the fugly truck intake until the FAST was approved and they went to 7100.

Done correctly, the engine described above could be a contender for the EMC Street Division class win. You would need the correctly ported heads, the correct valvetrain (which could be HR, very lightweight and affordable)

My highly-opinionated $.02


Jonthe more i think about this,the more i like your idea of using the 4.8 block bored to 3.90.since i already have the 243 heads and truck intake,it would be a little cheaper then the L92 combo.
i agree with you about the lightweight rotating assembly,not worth it for the minimal gains.if i was going all out and looking for every last point,sure. i will definately use the truck intake,i've seen a couple drag racers as well use that a few years ago with good results.
as far as the heads,i would just go with a GOOD VJ and bowl blend.that alone should get me to around 280cfm with the stock valves.plenty enough to feed the roughly 313 cubes and attain my power goals.
the key is to get the right cam/intake/exhaust combo(obviously).
the heads,pistons,headers and cam is where i'll budget most of the money,along with the necessary machining.
would be cool to use the GMPP ASA cam,love the thought of using off the shelf parts.but probably not ideal for the smaller cubes.although if i can get my hands on a ASA cam for cheap i might test it just to see what it would do.no matter what i'll have an expert spec me a cam.definately worth the minimal expense.
anybody have a 4.8 truck motor laying around they want to get rid of?lol.

i remember i thouhgt of a smilar idea awhile ago and asked the ppl on yellowbullet.
i always say alot of sbc destroked 400s making more power and rpm than 383s
came to the same conclusion..

Are coatings allowed? If so coating your piston tops would greatly help that detonation problem and allow you to unshroud the valves. Why spend your money on a new crank and destroke it when you could put that money to something you could get more power from? Or is this mainly for the per cube aspect of it?

Also Andy Dunn wrote a little thing on the EMC, http://racingarticles.com/article_racing-72.html
Its pretty neat

Are coatings allowed? If so coating your piston tops would greatly help that detonation problem and allow you to unshroud the valves. Why spend your money on a new crank and destroke it when you could put that money to something you could get more power from? Or is this mainly for the per cube aspect of it?

Also Andy Dunn wrote a little thing on the EMC, http://racingarticles.com/article_racing-72.html
Its pretty neat


FWIW, The "destroked" crank comes free with the 4.8L truck engine.

Andy Dunn makes some good points. Heads are Job 1, both in selection of the casting and modificatons they receive. The OP has good castings, 243 cathedral ports. Getting them correctly ported for this application would be most important and where the money shouLd go.

11.5:1 max with VP100 unleaded race fuel should not be a big detonation concern with 243 heads. I'm glad that they decided to use a decent fuel.

Intake manifold selection should, IMO, move up to the "top three" for street EMC competition.

My $.02

Jon

Are coatings allowed? If so coating your piston tops would greatly help that detonation problem and allow you to unshroud the valves. Why spend your money on a new crank and destroke it when you could put that money to something you could get more power from? Or is this mainly for the per cube aspect of it?

Also Andy Dunn wrote a little thing on the EMC, http://racingarticles.com/article_racing-72.html
Its pretty neat

Well considering that the 4.8 crankshaft is a 3.32'' stroke and every other ls power plant has a 3.622'' stroke, you can de-stroke a 6.0 cheap using stock 4.8 crank. Unless you wanted some off the wall stroke crank there would be no need to purchase an aftermarket crankshaft.

I will have to agree with old ss stroker on the l92 heads. If your goal is a high revving small displacement engine than the l92's would flow enough air into and out of the cylinder as quickly as possible in the upper rpm range for minimal cash. Granted this may not score many points in EMC but the volumetric efficiency at upper rpm would be better than a smaller/ more restrictive cylinder head on the same motor.

Another thought is to figure out what the counter weights are setup for on the 4.8 crank to determine if you need to rebalance for the larger piston/rod combo. You could possibly profile or knife edge the crank if the combo allowed you to. Just $.02

Ignorant move on my part. My bad.

Also is there a limit on compression? Or can you run as high as you want with the VP100 gas?

Apparently it seems there is a cap on the street class to 11.5:1. Havent checked to know 110% for sure but thats what was stated earlier in the thread

Ok. That would make sense. I have seen this advertised and covered in Hot Rod and Popular Hot Rodding and it is a great competition.

To the OP do it! I would love to do it... But funds and time are a couple of huge constraints at this point.

What about a near square stroked 5.3 ????
3.78 honed...small bore=fast flame=less detonation w/high cylinder pressure
3.76 crank....offset ground .140....compensate for shorter 6" small journal rod
replacement sbc scat rod= to new bolts and resize on pdrd metal stock rods
338 cubic inches easily fed by massaged 243s,possibly even epoxy runner
floors to reduce volume and strengthen port speed=important in this type
of dyno challenge 2500-6500 average power
definitely the truck intake and w/stock rockers and beehives w/tit retainers
you could custom cam it small perhaps 222-226 range...again to maximize
cylinder pressure @ low engine speeds
other than a few hundred bucks and a reputable machine shop to grind and
balance the crankshaft this combo would use cheap rods, the stock pistons
(flat w/no relief=efficient flame propagation) and minimal engine block
machining(hone)....just throwin' it out there

What about a near square stroked 5.3 ????
3.78 honed...small bore=fast flame=less detonation w/high cylinder pressure
3.76 crank....offset ground .140....compensate for shorter 6" small journal rod
replacement sbc scat rod= to new bolts and resize on pdrd metal stock rods
338 cubic inches easily fed by massaged 243s,possibly even epoxy runner
floors to reduce volume and strengthen port speed=important in this type
of dyno challenge 2500-6500 average power
definitely the truck intake and w/stock rockers and beehives w/tit retainers
you could custom cam it small perhaps 222-226 range...again to maximize
cylinder pressure @ low engine speeds
other than a few hundred bucks and a reputable machine shop to grind and
balance the crankshaft this combo would use cheap rods, the stock pistons
(flat w/no relief=efficient flame propagation) and minimal engine block
machining(hone)....just throwin' it out there

Hmmm...

There is considerable evidence that says 243s like bores 3.90 and up.

As I mentioned way back in this thread, the exact opposite approach for a ~340 cube EMC engine makes sense to some but not to others: 4.06 bore, 3.268 (4.8L) stroke and L92 heads. This is not the "velocity makes toque/power" approach, but then again neither are all of the GM L92 headed truck engines. Ever driven a 5000 lb.+ GM 2500 with an L92 headed engine? How'd the low-mid range feel with pedal to the metal?

Conventional "wisdom" says that can't work. Guess nobody told those engines.

Just throwin' more out there...


Jon

Don't get me wrong I'm a huge fan of big bore(unshroud 2.16 in valves)
and short stroke(less piston speed-ring friction) but I remember the first EMC
challenge where Beck Racing Engines bored a 307 block .060=3.9375
and used a 3.75 stroker crank....somewhat unconventional but I think he
finished in the top 5 and had a flat torque band 365" on pump gas
I also see some posts of people having 04-05 SUVs w/5.3 and one head is
a 243 and one a 799 on the same engine from GM. wierd ??????
I also marvel @ how GM strayed away from the cathedral port and back to
a huge rectangle (265cc). I have to think that with the floor raised and the
4.065 bore along w/376 inches it obviously makes hay:D

There was an article recently in popular hot rodding that had a small bore and long stroke gen 3 hemi making 700 hp. So it is obviously a great idea just exactly how you execute it.

There was an article recently in popular hot rodding that had a small bore and long stroke gen 3 hemi making 700 hp. So it is obviously a great idea just exactly how you execute it.

That doesnt seem very budget friendly but considering what you would have in custom pistons, balancing, valvetrain and other supporting parts that wouldnt be cheap either.