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Stroker VS stock displacement ?

 
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2jzmkiv



Joined: 22 May 2015
Posts: 82

PostPosted: Mon Jan 11, 2016 9:47 am    Post subject: Stroker VS stock displacement ? Reply with quote

It is said that "there is no replacement for displacement" but i do not know how true that is if you are aiming for hp for example in a 2jz engine would you increase the bore and stroke to 3.5 litres or keep displacement stock 3.0 and rev more ? thing that bothers me is almost every shop adverts stroker kits as if they are a key element in big hp numbers but i am confused because in greece extreme tuners actually under stroked a 4g63 engine to 1.8 litres and increased compression ratio to 17:1 and are making ridiculous numbers on the sheet so if you are aiming for hp high compression high revs lower displacement ? or low compression bigger displacement lower revs ? which way to go and why would someone go that way ?
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keithmac



Joined: 14 Nov 2010
Posts: 233

PostPosted: Mon Jan 11, 2016 11:08 am    Post subject: Reply with quote

Don't believe a word from Extreme Tuners, just have a 5 minute Google or a quick search on MLR ..
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Turboivo



Joined: 09 Mar 2006
Posts: 751
Location: Bulgaria

PostPosted: Mon Jan 11, 2016 11:25 am    Post subject: Reply with quote

keithmac wrote:
Don't believe a word from Extreme Tuners, ...


+1
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baldur



Joined: 12 Oct 2007
Posts: 623
Location: Reykjavik, Iceland

PostPosted: Mon Jan 11, 2016 11:30 am    Post subject: Reply with quote

Destroking is sometimes done to reduce piston speed and improve rod to stroke ratio. The resulting reduction in displacement usually doesn't help performance but the new engine may be able to survive and perform at higher engine speeds, and if done right this can be exploited for greater power output.
Also, racing classes often go by engine displacement so a bastard engine like this will have small displacement coupled with big engine cylinder heads and thus likely more valve area than existing engines of the same displacement.

On the 17:1 compression matter, this is not necessarily an advantage, such a high compression ratio in a chamber not designed from the ground up for such high compression is going to have an awkward shape that may hinder performance through excessive heat loss into the chamber walls as well as slow combustion.
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joe90



Joined: 19 Mar 2013
Posts: 382
Location: under the car

PostPosted: Mon Jan 11, 2016 2:36 pm    Post subject: Reply with quote

I'm not quite sure how you'd stroke a 2JZ out to 3.5 and make it all fit?
It's a smallish bore. Shortish rods and a smallish deck height.
OK lots of money and special parts.

Talking about these things and doing it are completely different.
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E30IS



Joined: 26 Jun 2008
Posts: 105

PostPosted: Mon Jan 11, 2016 3:09 pm    Post subject: Reply with quote

best longevity on bottom end comes from shorter stroke and smaller bore.

The tradeoff is the lower the torque, which doesn't matter when you have a properly geared and setup vehicle as its always about the hp curve in the operating band on a "track car".
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2jzmkiv



Joined: 22 May 2015
Posts: 82

PostPosted: Mon Jan 11, 2016 3:15 pm    Post subject: Reply with quote

joe90 wrote:
I'm not quite sure how you'd stroke a 2JZ out to 3.5 and make it all fit?
It's a smallish bore. Shortish rods and a smallish deck height.
OK lots of money and special parts.

Talking about these things and doing it are completely different.


96mm crank and 87.5mm pistons with appropriate connecting rod length would result in 3.5 if i am not mistaken brian crower and titan offers these kits but yes talking about these and doing them are different +1 on that Smile)
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2jzmkiv



Joined: 22 May 2015
Posts: 82

PostPosted: Mon Jan 11, 2016 3:33 pm    Post subject: Reply with quote

for example f1 engines and topfuel dragster engines are completely different from each other but f1 engines are capable of really high hp figures as well still not as much as topfuel dragster engines but what i am trying to say is what is the real difference between two ? and for instance if i was to apply the theory on a 2jz engine is it better to understroke rev higher run higher compression ratio to get crazy hp numbers or lower revs lower compression ratios & increase stroke & bore to get the same amount of hp ?
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riceracing



Joined: 27 Apr 2013
Posts: 288

PostPosted: Tue Jan 12, 2016 3:38 am    Post subject: Reply with quote

Turboivo wrote:
keithmac wrote:
Don't believe a word from Extreme Tuners, ...


+1


+2

Talk to my friend I sent you his contact details, and he told me ET are the biggest load of shitkunts in Greece by a long margin, my friend does all the high end work in Greece and he does not rate them highly (diplomatic edit) LOL.
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2jzmkiv



Joined: 22 May 2015
Posts: 82

PostPosted: Tue Jan 12, 2016 5:32 am    Post subject: Reply with quote

Don't know much about extreme tuners but i know they were asking prices like $20000 for billet porsche brake kit or something like that Very Happy
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E30IS



Joined: 26 Jun 2008
Posts: 105

PostPosted: Tue Jan 12, 2016 1:46 pm    Post subject: Reply with quote

2jzmkiv wrote:
for example f1 engines and topfuel dragster engines are completely different from each other but f1 engines are capable of really high hp figures as well still not as much as topfuel dragster engines but what i am trying to say is what is the real difference between two ? and for instance if i was to apply the theory on a 2jz engine is it better to understroke rev higher run higher compression ratio to get crazy hp numbers or lower revs lower compression ratios & increase stroke & bore to get the same amount of hp ?


depends on the application. there is no single answer.
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2jzmkiv



Joined: 22 May 2015
Posts: 82

PostPosted: Tue Jan 12, 2016 5:23 pm    Post subject: Reply with quote

E30IS wrote:
depends on the application. there is no single answer.


We can use the 2jz as an example would you stroke it lower compression or leave stock displacement try and get more revs and also raise compression ?
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E30IS



Joined: 26 Jun 2008
Posts: 105

PostPosted: Tue Jan 12, 2016 8:32 pm    Post subject: Reply with quote

2jzmkiv wrote:
E30IS wrote:
depends on the application. there is no single answer.


We can use the 2jz as an example would you stroke it lower compression or leave stock displacement try and get more revs and also raise compression ?


application means street, road race, circuit, drags etc you need to define it
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2jzmkiv



Joined: 22 May 2015
Posts: 82

PostPosted: Tue Jan 12, 2016 10:50 pm    Post subject: Reply with quote

in this case it would be drag yes but please do tell me how it would be in other applications as i believe knowing their differences i can compare relate and grasp it quicker Smile
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E30IS



Joined: 26 Jun 2008
Posts: 105

PostPosted: Wed Jan 13, 2016 1:50 pm    Post subject: Reply with quote

2jzmkiv wrote:
in this case it would be drag yes but please do tell me how it would be in other applications as i believe knowing their differences i can compare relate and grasp it quicker Smile


drag racing id use a smaller higher revving engine as you only need a narrow powerband and the engine never sees low rpm, on the street more cubic inches will be more useable IMO as the power is available at lower rpm
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