Refresh951's Hybrid Ultra Stroker Build - Page 5 - Rennlist - Porsche Discussion Forums

Notices

Refresh951's Hybrid Ultra Stroker Build

Old 12-12-2012, 06:35 PM
  #61  
1987Porsche944WithRealLongName
User
 
Join Date: Feb 2009
Posts: 304
Default

So if you were to just do an offset grind and not touch the bores how would that go? Would the change in displacement be too small to make it worth it? Would the pistons just not work with the bore coating?
1987Porsche944WithRealLongName is offline  
Old 12-12-2012, 07:26 PM
  #62  
refresh951
Moderator
Rennlist Member
Thread Starter
 
refresh951's Avatar
 
Join Date: Jun 2010
Location: Marietta, Georgia
Posts: 3,329
Default

Originally Posted by 1987Porsche944WithRealLongName View Post
So if you were to just do an offset grind and not touch the bores how would that go? Would the change in displacement be too small to make it worth it? Would the pistons just not work with the bore coating?

I have not looked at that. It may be possible to use the Mitsubishi rods with stock coated pistons. The rods would need to modified to take the stock wrist pin (0.945"). Not sure of the compression height on the stock pistons. Seems possible. I still like the idea of sleeves to improve reliability.
refresh951 is offline  
Old 12-12-2012, 08:49 PM
  #63  
Reimu
Super User
 
Reimu's Avatar
 
Join Date: Jun 2006
Location: NC Triad
Posts: 2,600
Default

Originally Posted by 1987Porsche944WithRealLongName View Post
So if you were to just do an offset grind and not touch the bores how would that go? Would the change in displacement be too small to make it worth it? Would the pistons just not work with the bore coating?
If my math is right (and it most likely isn't) that would be just at 2.7 liters not accounting for whatever modification is done to the pistons. Surely a performance increase.
Reimu is offline  
Old 12-12-2012, 08:50 PM
  #64  
333pg333
Addict
Rennlist Member
 
333pg333's Avatar
 
Join Date: Feb 2006
Location: Australia
Posts: 18,464
Default

Originally Posted by URG8RB8 View Post
Patrick: That is a very long and disappointing story. Car has been in Oklahoma for nearly three years now! Finally back to LR this morning, maybe will have something soon. Don't really want to say much about this nightmare. I will post results once completed.
These special builds take a lot of patience. Good luck!
333pg333 is offline  
Old 12-13-2012, 12:32 PM
  #65  
CyCloNe!
Addict
Rennlist Member
 
CyCloNe!'s Avatar
 
Join Date: Dec 2009
Location: Virginia Beach, VA 23464
Posts: 3,212
Default

Of course if you didn't want to go crazy with horsepower you could always use the chevy pistons increase the pin size and use the stock rods. Of course you would have to bore the block, sleeve it and fill it. I think the chevy pins are what .92 and porshce pins .94. The down side is the rod torque limit is less than the mitsu forged rods. Stock rods are good for what like 400whp (475-500chp) or something?
CyCloNe! is offline  
Old 12-13-2012, 12:46 PM
  #66  
Rogue_Ant
Addict
Rennlist Member

Rennlist
Small Business Partner

 
Rogue_Ant's Avatar
 
Join Date: May 2006
Location: Denver
Posts: 5,252
Default

Originally Posted by 1987Porsche944WithRealLongName View Post
So if you were to just do an offset grind and not touch the bores how would that go? Would the change in displacement be too small to make it worth it? Would the pistons just not work with the bore coating?
Originally Posted by refresh951 View Post
I have not looked at that. It may be possible to use the Mitsubishi rods with stock coated pistons. The rods would need to modified to take the stock wrist pin (0.945"). Not sure of the compression height on the stock pistons. Seems possible. I still like the idea of sleeves to improve reliability.
The Mitsu rods are nearly identical length to factory... So if you want to use stock pistons, then the pin height of the piston wouldn't allow for much of any offset grind. So, there would be no displacement increase from just using the Mitsu rods. Also, the rods would still need machined to accept the larger pin diameter of the factory piston (24mm, vs 22mm).

Originally Posted by CyCloNe! View Post
Of course if you didn't want to go crazy with horsepower you could always use the chevy pistons increase the pin size and use the stock rods. Of course you would have to bore the block, sleeve it and fill it. I think the chevy pins are what .92 and porshce pins .94. The down side is the rod torque limit is less than the mitsu forged rods. Stock rods are good for what like 400whp (475-500chp) or something?
The stock pistons are going to go further than the stock rods. The single most stressed component in the engine is the connecting rod. And if you are only changing one thing - then the rod should be what you change.
Rogue_Ant is offline  
Old 12-13-2012, 02:11 PM
  #67  
CyCloNe!
Addict
Rennlist Member
 
CyCloNe!'s Avatar
 
Join Date: Dec 2009
Location: Virginia Beach, VA 23464
Posts: 3,212
Default

Originally Posted by Rogue_Ant View Post
The Mitsu rods are nearly identical length to factory... So if you want to use stock pistons, then the pin height of the piston wouldn't allow for much of any offset grind. So, there would be no displacement increase from just using the Mitsu rods. Also, the rods would still need machined to accept the larger pin diameter of the factory piston (24mm, vs 22mm).



The stock pistons are going to go further than the stock rods. The single most stressed component in the engine is the connecting rod. And if you are only changing one thing - then the rod should be what you change.
So basically if you going for a cheaper budget build for increased power the one major beneficial component to replace would be the rods. Which wouldn't help displacement but would help horsepower potential?
CyCloNe! is offline  
Old 12-13-2012, 02:19 PM
  #68  
Rogue_Ant
Addict
Rennlist Member

Rennlist
Small Business Partner

 
Rogue_Ant's Avatar
 
Join Date: May 2006
Location: Denver
Posts: 5,252
Default

Yep.
Rogue_Ant is offline  
Old 12-13-2012, 02:34 PM
  #69  
CyCloNe!
Addict
Rennlist Member
 
CyCloNe!'s Avatar
 
Join Date: Dec 2009
Location: Virginia Beach, VA 23464
Posts: 3,212
Default

well say you use stock pistons, mitsu rods, what other methods can you use to increase displacement or compression? Reason I ask is to gain better low end response without the needs for boring over and such. I've never built an engine but I am always interested learning new things.
CyCloNe! is offline  
Old 12-13-2012, 02:39 PM
  #70  
Rogue_Ant
Addict
Rennlist Member

Rennlist
Small Business Partner

 
Rogue_Ant's Avatar
 
Join Date: May 2006
Location: Denver
Posts: 5,252
Default

Not much ways to increase displacement without changing the pistons...
There are ways, but usually none more economical than Sid's approach.

I suppose you could get pistons meant to work with the stock bore and with a higher placed pin, and then offset grind the crank to match, which would give you added stroke and therefore increase displacement. But then you have to consider the cost of alusil compatible pistons vs sleeving and regular pistons.
Rogue_Ant is offline  
Old 12-13-2012, 11:58 PM
  #71  
refresh951
Moderator
Rennlist Member
Thread Starter
 
refresh951's Avatar
 
Join Date: Jun 2010
Location: Marietta, Georgia
Posts: 3,329
Default

Slightly reduced stroke to 94.85 mm. This lowered CR to 8.0:1. I think it is going to take on the order of 23-24 psi to hit my goal of 550 rwhp.
refresh951 is offline  
Old 12-14-2012, 12:41 PM
  #72  
CyCloNe!
Addict
Rennlist Member
 
CyCloNe!'s Avatar
 
Join Date: Dec 2009
Location: Virginia Beach, VA 23464
Posts: 3,212
Default

Originally Posted by refresh951 View Post
Slightly reduced stroke to 94.85 mm. This lowered CR to 8.0:1. I think it is going to take on the order of 23-24 psi to hit my goal of 550 rwhp.
Shawn did you decide which turbo your going with on this build? I know in the first post you mentioned the GT3582R turbo, is that still in the plan?
CyCloNe! is offline  
Old 12-14-2012, 12:56 PM
  #73  
dnovak
Addict
Rennlist Member
 
dnovak's Avatar
 
Join Date: May 2011
Location: Erie Colorado
Posts: 392
Default

I vote for a VNT
dnovak is offline  
Old 12-14-2012, 10:00 PM
  #74  
refresh951
Moderator
Rennlist Member
Thread Starter
 
refresh951's Avatar
 
Join Date: Jun 2010
Location: Marietta, Georgia
Posts: 3,329
Default

Originally Posted by CyCloNe! View Post
Shawn did you decide which turbo your going with on this build? I know in the first post you mentioned the GT3582R turbo, is that still in the plan?
Pretty sure on the GT3583R at this point. Still looking at it and will make a final decision by the first of the year.
refresh951 is offline  
Old 12-15-2012, 07:37 PM
  #75  
refresh951
Moderator
Rennlist Member
Thread Starter
 
refresh951's Avatar
 
Join Date: Jun 2010
Location: Marietta, Georgia
Posts: 3,329
Default

Got the block back from the machine shop today, cleaned and fresh hone. Cleaned parts all day getting ready for re-assembly. Crank should be done in a few days.



refresh951 is offline  

Thread Tools
Search this Thread
Quick Reply: Refresh951's Hybrid Ultra Stroker Build


Contact Us Advertising Cookie Policy Privacy Statement Terms of Service

© 2018 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: