Destroking - Facts or fiction

[Mike T]

Not sure how to point out what I believe is the obvious but here goes.....

Lets say we use the same top end on three different short blocks. Top end would consist of Champion irons and a roller cam that pulls to 5500. Our 3 short blocks are destroked, stock stroke and stroker.

The engines are all ran at 20 psi and to a max rpm of 5500. I do not see how it is possible for the shorter stoke (smaller ci) to out perform the longer strokes.

At the relatively low rpm that our engines typically operate piston speed and crank centerline wouldn't even factor.

Get into the 6k+ rpm territory and sub 10 second power maybe the short stroke would be something to consider.

 

[dank GN]

Not sure how to point out what I believe is the obvious but here goes.....

Lets say we use the same top end on three different short blocks. Top end would consist of Champion irons and a roller cam that pulls to 5500. Our 3 short blocks are destroked, stock stroke and stroker.

The engines are all ran at 20 psi and to a max rpm of 5500. I do not see how it is possible for the shorter stoke (smaller ci) to out perform the longer strokes.

At the relatively low rpm that our engines typically operate piston speed and crank centerline wouldn't even factor.

Get into the 6k+ rpm territory and sub 10 second power maybe the short stroke would be something to consider.

You are correct but the point I believe is being made is if you de stroke a motor and raise the peak rpm that it would perform as well as a stroked motor that is running at a low peak rpm . If you guys really want to see what a destrroked motor can do just look a the Buick Indy motors . I was lucky enough to have some Indy parts . I acquired enough parts to build a Indy motor I was just missing the most important part the block . I think it would be interesting to build a destroked motor but truthfully for what 90% of the Buick community would use a motor for destroking would be the wrong combination imo. They need power to come in down low for the street driving and need power to come in ASAP . After feeling the difference of what my 4.6L 281 stroker motor brings to the table I would suggest more ppl to stroke there motor out . The power comes in super fast and hard . Here are some pictures of Buick’s indy setup

 

[NY Twin Turbo]

GOT FLOW ?

View attachment 329382

Now that's what I'm talking about! Yea baby!

Looks like you can suck a small child down those runners!

 

[Mike T]

You are correct but the point I believe is being made is if you de stroke a motor and raise the peak rpm that it would perform as well as a stroked motor that is running at a low peak rpm . If you guys really want to see what a destrroked motor can do just look a the Buick Indy motors . I was lucky enough to have some Indy parts . I acquired enough parts to build a Indy motor I was just missing the most important part the block . I think it would be interesting to build a destroked motor but truthfully for what 90% of the Buick community would use a motor for destroking would be the wrong combination imo. They need power to come in down low for the street driving and need power to come in ASAP . After feeling the difference of what my 4.6L 281 stroker motor brings to the table I would suggest more ppl to stroke there motor out . The power comes in super fast and hard . Here are some pictures of Buick’s indy setup

I always like to break it down simple as possible. Some of this stuff could overwhelm and confuse a guy simply looking to go 10's.
He may go out and build a destroked motor thinking it the magic bullet when his stock stroke is more than adequate.

 

[dank GN]

You want to see runners check out These pics I found of don wangs beautiful fabrication skills

 

[NY Twin Turbo]

I always like to break it down simple as possible. Some of this stuff could overwhelm and confuse a guy simply looking to go 10's.
He may go out and build a destroked motor thinking it the magic bullet when his stock stroke is more than adequate.

This is important to mention. I agree with you.

To all you new guys out there that want simple quick street cars that pull hard and are pleasant to drive, I think you should consider the discussion taking place here is more about theory. I wouldn't go ahead and start telling your engine builder you want this or that just because you read it here in this thread. The combinations for a reliable, good running 500 horsepower street driven TR are already tested and proven.

For the TR veterans, racers, and mechanics. It's a different situation. Spare blocks, cranks, and other engine parts laying around. Along with years of tinkering experience and knowledge can greatly simplify trying different approaches to building a Buick V6. But don't get me wrong, an experiment in engine building is never simple, especially when it doesn't quite turn out as expected.

In the end, it's these guys who share the characteristics of how these engines behave with the people they will build engines for. So this way you can make the decision of what you want when they build a motor for you.

 

[rag231]

What about this? Stoked or destroked? Can you imagine the what if?

 

[Mr.Spool]

The engines are all ran at 20 psi and to a max rpm of 5500. I do not see how it is possible for the shorter stoke (smaller ci) to out perform the longer strokes.

mike the point of the different build is you wouldnt run them the same.there is a point where they would make the same power

 

[Mr.Spool]

After feeling the difference of what my 4.6L 281 stroker motor brings to the table I would suggest more ppl to stroke there motor out . The power comes in super fast and hard .

your feeling the torque and ability to drive the turbo,which seems easier with the bigger motor.the destroked stuff thrives at higher rpm.

 

[Mr.Spool]

Get into the 6k+ rpm territory

would need to go much higher.ive spun a stock stroke 7200 rpm

 

[Mr.Spool]

They need power to come in down low for the street driving and need power to come in ASAP .

they are also alot more fun that way,to me the destroked stuff is for the track more.

 

[Mike T]

would need to go much higher.ive spun a stock stroke 7200 rpm

That statement is key for guys that don't know when a shorter stoke becomes beneficial.

 

[Mr.Spool]

what should also be considered is the drivetrain approach.you dont want to spin a 200 7500/8000+rpm.

 

[NY Twin Turbo]

would need to go much higher.ive spun a stock stroke 7200 rpm

My stock stroke goes there as well.

 

[turbo89]

mike the point of the different build is you wouldnt run them the same.there is a point where they would make the same power

This X 2 .. no doubt whatsoever .. smaller motor is FASTER in the same car... fight it all you want

 

[turbo89]

they are also alot more fun that way,to me the destroked stuff is for the track more.

Not so much.. real real treat in the street with a smaller motor

 

[turbo89]

what should also be considered is the drivetrain approach.you dont want to spin a 200 7500/8000+rpm.

No issues at 7200

 

[Ttype6]

real treat in the street with a smaller motor

Only at full song with a lot of boost.
Every other quality that you would want in a street engine and could measure would be lacking and disappointing in the smaller engine on the street. There is zero chance that this thread is going to cause me to yank my 273 and install a smaller engine than I had before. The valve train you would need to operate at such high rpm would need a lot of maintenance and monitoring. High rpm/short stroke = racing. Low rpm torque/big cubic inches = street. I know it will only go well into the nines,but I can live with that with a big smile on my face with a fair amount of fear mixed in.

 

[turbo89]

Only at full song with a lot of boost.
Every other quality that you would want in a street engine and could measure would be lacking and disappointing in the smaller engine on the street. There is zero chance that this thread is going to cause me to yank my 273 and install a smaller engine than I had before. The valve train you would need to operate at such high rpm would need a lot of maintenance and monitoring. High rpm/short stroke = racing. Low rpm torque/big cubic inches = street. I know it will only go well into the nines,but I can live with that with a big smile on my face with a fair amount of fear mixed in.

Im ok if there is zero chance of people switching.. there loss not mine.. been on both sides and know what the reality is ... if you cant have an open mind.. never gonna grow

 

[turbobuick]

It would depend heavily on the turbo you are running and what you are trying to accomplish. You are almost always better with a bigger air pump! Unless of course in a high HP app where a shorter stroke crank is maybe a little stronger will have a little less flex, especially with an even fire split journal rod??

I ran a 274" motor with production style heads and a PTE88 and had zero issues making power to 7800, actually the car never saw less than 7200 in an entire pass and ran over 170!

Love the engine porn that Indy stuff is way cool!