Pelican Parts Forums

Pelican Parts Forums (http://forums.pelicanparts.com/)
-   Porsche 924/944/968 Technical Forum (http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/)
-   -   Building a stroker/wet sleeved 951S - Borg Warner EFR 6258 (http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/970189-building-stroker-wet-sleeved-951s-borg-warner-efr-6258-a.html)

PDX-944 09-14-2017 09:44 AM

Building a stroker/wet sleeved 951S - Borg Warner EFR 6258
 
I had started another thread inquiring about doing a rebuild, and some of the options. I might as well start this as a build thread now that I'm going to get started - I still need help making some decisions.

First off, heres what I have

951S Silver Rose
Wolf3D V400 EMS using MAP sensor
J&S Knocksafe (tuned for 16psi on premium fuel, tunable via laptop)
B&B Header
EFR 6258 Turbo with internal recirc valve
3" Stainless downpipe (ceramic coated)
4" Lindsey Racing stainless cat-back
Custom oil cooler
Custom aluminum intake piping (larger diameter)
Aluminum flywheel
Spec Stage II clutch
Tial Wastegate
72# injectors
Aluminum fuel rail
Adjustable Lindsey "stock location" FPR


So Im looking at 3.1-3.2L wet sleeved and stroked.

I have access to a machine shop that from what Im told through my connection, makes anything. They can pull apart a motor or trans, figure out what they need, and just make it.
I can have this done at material cost.

Im going in there tomorrow to meet them for the first time with the person who I have the connection through, and I'm looking to figure out what all to ask about:

- If they can machine and wet sleeve the motor/deck
- Offset grind or simply make me an offset lighter crank (they can)
- They can make a cam from scratch, but I have no idea what they would make me or what to ask for
- Whatever else they recommend that they can do for me during the build.

What I'm trying to figure out and piece together right now:

Possible 3.31L
Deck Height = 9.05”
Bore = 106mm = 4.17”
Stroke = 94mm = 3.7”
Rod Length = 145.288mm = 5.72”
Chamber Volume = 56cc
Gasket Thickness = .039 or .055"
Piston Dome Volume= -31
Pin Height (Compression Height) = 1.425?

Or, same as above, with 104mm bore, I end up with a 3.2L


This is my first build of this depth, but I'm determined to make this work, and it will be done before next race season.

This is my hillclimb and autocross car. I compete in a series of hillclimbs locally and the car is already doing very well, but compression is getting poor, and I need to rebuild between seasons.

Do the above numbers look reasonable? Im a bit unsure about the ones with question marks, and could use advice and guidance during this!

Ive been reading every thread out there that I can find about other builds, theyre all over the board and most end at 2.85L


http://forums.pelicanparts.com/uploa...1505413649.jpg

v2rocket_aka944 09-14-2017 10:51 AM

Hi,
The offset builds use Mitsubishi 150mm rods, not the shortened Pauter 944-type.
The offset grind takes the stock crank down to a 45mm rod journal (Mitsu size).

I don't know if there is enough physical space in the block/girdle for a 52mm (944 size) journal and rods at 94mm stroke.

Some useful figures to consider in your calcs (all stock parts)
Head cc
8v ~56cc
16v ~42cc

HG thickness
1mm (0.039")
optional 1.4mm (0.055")

Deck height nominally ~230mm (sleeving requires the deck to be cut flat so your final deck height will be less)

So if you did use Mitsu parts...

230 deck height - 150 rod length - 47 (1/2 of 94 mm stroke) = 33mm piston pin (compression) height.

Tip: if you wanted to use shorter rods than Mitsu, and there was sufficient room in the block, you could save a lot of $$ by having the rod journals cut to 2.00" and using 5.7" Chevy inline 6 rods, about $75 each vs $230 each for the 944 stuff.

PDX-944 09-14-2017 11:30 AM

according to that then -

http://forums.pelicanparts.com/uploa...1505417248.jpg

exactly 0 clearance.

and if I go with the thicker HG (.055) it brings the CR to 9.34:1 but still need a hair more deck clearance, which should bring CR down in any case. hmm

v2rocket_aka944 09-14-2017 11:44 AM

the 94+mm stroke cars i am familiar with have ended up with the piston below deck "down in the hole" 2-3mm.

your numbers above but 2mm down makes 8.3:1

PDX-944 09-14-2017 11:48 AM

Quote:

Originally Posted by v2rocket_aka944 (Post 9737725)
the 94+mm stroke cars i am familiar with have ended up with the piston below deck "down in the hole" 2-3mm.

your numbers above but 2mm down makes 8.3:1

so the question is... what gives? what do I need to change? shorter rods as you mentioned above?

v2rocket_aka944 09-14-2017 02:34 PM

the numbers you plugged into that calculator suggest using the 150mm mitsu rods + 33mm piston height which is right for 0 deck.

to get the "down in the hole" like the others have used you would use a piston with a shorter height - 30-31mm or so, whatever that is in inches.

i'd be interested in knowing your shop's price for crank work (or a custom crank).

PDX-944 09-14-2017 03:32 PM

Quote:

Originally Posted by v2rocket_aka944 (Post 9737934)
the numbers you plugged into that calculator suggest using the 150mm mitsu rods + 33mm piston height which is right for 0 deck.

to get the "down in the hole" like the others have used you would use a piston with a shorter height - 30-31mm or so, whatever that is in inches.

i'd be interested in knowing your shop's price for crank work (or a custom crank).

ill find that out tomorrow!

looks like im getting slowly closer to a plan. exciting exciting... cant wait for the torque next year

PDX-944 09-19-2017 02:25 PM

Possible 3.31L
Deck Height = 9.05”
Bore = 106mm = 4.17” (MID Sleeves)
Stroke = 94mm = 3.7” (Offset grind, can use 2.5 crank?)
Rod Length = 150mm (Mistubishi rods)
Chamber Volume = 56cc
Gasket Thickness = .039 or .055"
Piston Dome Volume= -32
Pin Height (Compression Height) = 1.3"

This still has my piston above deck height by .01" though. Ideas?

PDX-944 10-03-2017 03:23 PM

I have located a 3.0 crank, and a place to do the offset grind to 94mm.
Also I have 944enhancement that can do the wet sleeving/boring to 106mm, and supply custom pistons with gapped rings.

but I need to figure out which rods and bearings to get.

someone said mitsu, and another said small block chevy for bearings... but im struggling to figure that out.

the mitsu someone recommended was 150mm length (1.3" pin height), but that lands me .005 over deck height, with 9.3x:1 CR

if I calculate with 149mm rods (1.26" pin height) I end up at .07 deck clearance, 8.37:1 CR
That looks much better right? but how to I get 149mm rods? do I want to go with mitsu or other? I have to decide before I send the crank for grinding.

Deck height 9.05"
Bore 4.17" (106mm)
Stroke 3.7" (94mm)
Rod Length 5.87" (149mm)
Chamber Vol 56cc
Gasket Thickness .039"
Piston Dome -32cc
Pin Height 1.26" (32mm)

Equals deck clearance .07"
CR 8.37:1
Engine size 3.31L
Rod Ratio 1.59:1
Max Rod Angle 18.37 Degrees

Ideas on rods and bearings?

PDX-944 01-26-2018 04:44 PM

Well, things are in the works. The head work is completed by Michael Mount, the block is almost finished with the balance shaft delete and all. I have the offset crank and have ordered my rods and bearings. Just waiting on custom Pistons that Michael has ordered for me.

That brings me to a question I'm trying to figure out - I have 72 pound injectors and the stock fuel pump. Will those be sufficient? I will be keeping the small efr turbo for now and running about 18 lb of boost, the motor will be a 3.25 L. I'm not sure how much power to expect from that on Pump Fuel.

Nowanker 02-08-2018 04:42 PM

Sorry I just found this thread!
Went down the 3.2L(+) stroker route... 3.0 block bored/sleeved, 3.0 crank, Carillo rods.
Set up with the balance shaft delete.
Still smooth as glass without them, BUT: harmonics in the engine caused some important pieces to crack, namely the fuel rail and oil pump pickup.
Fuel fire happened in the garage and was no big deal, pump pickup failure not as lucky. Apparently these pumps will produce full pressure with mostly air. Never had a low pressure indication until the end of the season when I saw it had dropped a little at idle.
Cracked pickup, ruined bearings, scored pistons and cylinders.
Bore, hone, new pistons, bearings, etc. Braced the pickup to support the bottom better... cracked in a different place after another season, same net result
Disinclined to continue the adventure... will be parting out the salvageable items!
If I was starting from scratch, I'd leave the balance shafts...
Combo makes awesome power!

PDX-944 02-08-2018 06:28 PM

What kind of power were you at? What turbo? Fuel pump? Injector size?

I have a custom fuel rail in not overly concerned about, oil pickup I will reinforce for that reason as well.
I plan to keep Rev limit at 6850 probably, not looking for crazy numbers really, moderate boost.

flash968 02-09-2018 12:48 AM

when i obrounded my cylinders a few years ago (don't ask), i considered a sleeve setup. i had done it before in other engines, and was successful.

then i started looking into it. due to the open deck design, and that i was going to be running about 7lbs boost, the sleeve company (the one that everybody knows) warned me off. they said they felt that the cylinders would move around enough under boost to cause repeated gasket failure. they would not guarantee against it. they said that if i stayed normally aspirated, it would be fine, but not under boost, and that was at only 7lbs.

i also spoke to arguably the best guy in the country on stroking these engines, and he felt the same way.

so, i just went up one size on pistons, carillo rods, did some porting and polishing, and balanced the crap out of everything.

Nowanker 02-09-2018 12:25 PM

Did 365 at the wheels @ 16 psi.
Turbonetics t3/t4 (too small?). Awesome torque, no lag.
Electromotive management/big injectors/Bosch 044 pump
Kept the redline around 6k.
I bought he engine used, supposedly fresh from a big name race shop back east. It was f*cked up from the start... they put the main bearing shells in upside down and starved the crank for oil. Lucky I looked.
It used Rodeck (dry) sleeves, they're more famous for sprint car motors I think. No issues with headgaskets, but it did have O rings on the sleeves with matching grooves cut into the head.
I think the 3 liter block casting supports the cylinders a little farther up than a 2.5, but it's been a lonnnnng time since I saw a 2.5 apart.
2nd go 'round, I braced the bottom of the pickup to the block, to stop it vibrating like a pendulum. 3rd time I pulled it apart I found a spiral fracture at the top of the pickup, a little bit down from the flange.
I quit....

PDX-944 02-09-2018 09:01 PM

the 3 liter block is supported while the 2.5 is not.
im surprised... my 2.5 made that power. im expecting closer to 500 this time around. if head gasket begins being an issue ill probably o-ring it or look into deck plates. cross that bridge when i get there....

Nowanker 02-10-2018 05:14 PM

^^ The 365 was on a Dynapac which seemed pretty stingy with the numbers compared to a Dynojet, but I suspect that my turbine housing was actually too small for the displacement. Car had ZERO lag... Made an awesome road racer!
Where is Wilsonville? We're in the SF Bay Area, but planning to relocate to somewhere around Bend next year.

PDX-944 02-11-2018 12:19 PM

i actually live in newberg now, which is about 15 minutes from wilsonville. its just at the south end of portland - a few hours away from bend. not much racing in the bend area... one autocross club (Autocross Club of Central Oregon) but they have had no venues for years until they finally found one last year for one event.
Oregon Raceway Park isnt too far away though


All times are GMT -8. The time now is 01:21 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website


DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.