500whp goal on s4 block pinning/studing questions
11-26-12, 10:31 PM
#1
500whp goal on s4 block pinning/studing questions
im gonna be rebuling my motor for next summer for a 475-500whp goal . im gonna be porting the motor and using ra superseals again and all the other goodies etc. now my question is i hear alot about rear iron crack on the s4 engines. i want to keep everything s4 so i dont know really wat studding / pinning motor is .or were to get it done. i will be doing the rebuild myself again .please dont come on here bashing
11-27-12, 09:24 AM
#4
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why don't you just buy an S5 rear plate while its apart? that's the only thing you need to keep it from cracking, besides a good ecu
11-27-12, 10:30 AM
#5
i am leaning more towards studding over doweling, the dowels are hollow and tend to still allow the engine to break under enough force. studs are just that, solid studs that run through the length of the engine and replace the much smaller factory tension bolts, the factory tension bolts are smaller than the pilot holes in the block which does not add any rigidity to the engine over studding it. studding also doesn't require removing as much material from the block, allowing it to retain more structural integrity.
doweling will still allow the series 4 and thin cast series 5 blocks to put out over 500 horsepower without breaking the rear iron, but severe detonation can still twist a doweled engine apart(likely you will lose a rotor first anyways though).
doweling is the cheaper method(2 spare 13B dowel sets can be found for about $10-20, $50 for long tension bolts, plus machining labor at about $300) and i would say is fine for engines up to the 700whp range, studding has been proven to work on engines putting out well over 1000whp but stud kits can be a bit pricey depending on the materials used(stud kits range from $150-350 and still require the $300 in milling labor).
either method require line bore milling of the whole block shell.
the thick casting s5 turbo rear iron(not all series 5 are thick cast, it was a late model revision before the introduction of the REW) even with factory dowels allows the engine a little more breathing room up to the 500whp range without any read modification to the block otherwise. the REW(FD3S) has thick castings on both front AND rear plate to allow it a modest 650whp range for the engine, before adding in detonation destruction probability.
Last edited by RotaryEvolution; 11-27-12 at 10:47 AM.
11-27-12, 10:53 AM
#7
they're an upgrade but still not quite what i would consider true studs.
see the gaps between the studs and the rotor housings? that allows room for the engine to move under stress still. their kit is good for those unwilling to mill the block for a true stud kit as it will still clamp the engine better than the rather stringent stock tension bolts. a true stud kit utilizes the surface area between the stud to engine contact as a holding factor. basically a rod in a direct pilot hole will not allow the 2 parts to move away from one another unless the bolt itself shears or pulls the metal to a degree. the factory dowels are still doing the majority of the work.
the thing you have to consider when these engines break is the rear iron is trying to twist(the whole engine actually, but for simplicity sake just put your hands together and turn them opposite directions from each other), say where the front iron would be completely stationary.
true studs do NOT have to replace all of the tension bolts to still add a bit of structural rigidity to the engine. most stud kits come in 4/6 or 8 stud kits, less machining required versus the complete 17 main tension bolts that hold the engine together. milling the whole block for all oversize studs would definitely be a chore.
see the gaps between the studs and the rotor housings? that allows room for the engine to move under stress still. their kit is good for those unwilling to mill the block for a true stud kit as it will still clamp the engine better than the rather stringent stock tension bolts. a true stud kit utilizes the surface area between the stud to engine contact as a holding factor. basically a rod in a direct pilot hole will not allow the 2 parts to move away from one another unless the bolt itself shears or pulls the metal to a degree. the factory dowels are still doing the majority of the work.
the thing you have to consider when these engines break is the rear iron is trying to twist(the whole engine actually, but for simplicity sake just put your hands together and turn them opposite directions from each other), say where the front iron would be completely stationary.
true studs do NOT have to replace all of the tension bolts to still add a bit of structural rigidity to the engine. most stud kits come in 4/6 or 8 stud kits, less machining required versus the complete 17 main tension bolts that hold the engine together. milling the whole block for all oversize studs would definitely be a chore.
Last edited by RotaryEvolution; 11-27-12 at 11:01 AM.
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11-27-12, 11:00 AM
#8
I've had guys make over 1000rwhp with just our stud kit. I've also made over 500rwhp on a S4 that was a bone stock rebuild. If you cannot properly machine a engine, don't machine it, you will make it worse in the end...
For you I would do our stud kit, and S5 plates...
For you I would do our stud kit, and S5 plates...
11-27-12, 11:01 AM
#9
11-27-12, 11:04 AM
#10
i've also seen stock series 4 engines make over 500whp and stock REW over 750whp without any studding or plate revisions.
it's a safety measure and i don't disagree that your studs aren't helpful to the engine and are probably the easiest way to add strength but still not ideal if hints of detonation occur. engine damage will still likely occur but it may save more parts if the engine doesn't begin twisting, allowing rotor to housing contacts destroying more costly and hard to find parts as time goes on.
of course this also assumes not using factory seals, because they will chew up a CC regardless of this whole debate. i just prefer to look at the big picture, saving as many parts as possible in failure scenarios and is just my opinion.
it's a safety measure and i don't disagree that your studs aren't helpful to the engine and are probably the easiest way to add strength but still not ideal if hints of detonation occur. engine damage will still likely occur but it may save more parts if the engine doesn't begin twisting, allowing rotor to housing contacts destroying more costly and hard to find parts as time goes on.
of course this also assumes not using factory seals, because they will chew up a CC regardless of this whole debate. i just prefer to look at the big picture, saving as many parts as possible in failure scenarios and is just my opinion.
Last edited by RotaryEvolution; 11-27-12 at 11:09 AM.
11-27-12, 04:45 PM
#12
i dont get oversized stud kits.. isnt the extra space around the factory studs there to absorb expansion of the housing during extreme pressure? if you got rid of this expansion space, wouldnt that lead to more cracked irons because there is nothing to absorb the pressure. i would think turblown's kit is the way to go becuase is leaves this space
11-27-12, 06:58 PM
#13
The thermal expansion rate of Aluminum is nearly double that of steel, so unless you get the steel significantly hotter than the Aluminum it should actually work the other way around, creating a minute gap between the dowels and housings.
edit: in case you don't know this, when you heat up a metal ring the inside diameter increases because the whole piece expands, so for the same temperature increase the inner ring of the housing that holds the dowel would increase its diameter more than the increase of the outside diameter of the dowel (about 1.7 times as much if my math is right).
edit: in case you don't know this, when you heat up a metal ring the inside diameter increases because the whole piece expands, so for the same temperature increase the inner ring of the housing that holds the dowel would increase its diameter more than the increase of the outside diameter of the dowel (about 1.7 times as much if my math is right).
11-27-12, 11:45 PM
#14
alot of good info . so i can use s4 everything . s5 rear plate . and turblown drop in stud kit and be all set for 500whp? i wont be running 500hp all the time . thats my highboost type of thing im looking for like 450ish normal . going with the borgwarner s366
11-28-12, 01:19 AM
#15
talking head
goopy bolt kit
. its about harmonics as much as anything ... plates dont always break,, sometimes the through bolts also sheer off
using two different diameter or material metals will give the engine resistance to two different harmonic frequencies that could be destructive to either bolt or engine plate
these goopy kits allow you this twin harmonic dampening , take the least material out , have threads to stretch at only one end , and address the front plate issue with thread purchase deeper into the front plate
all at minimal cost and only requires a drill press and care
other tricks include rubber sleeving or silicone bonding the middle of the normal through bolts
- something mazda found necessary in competition when they where breaking through bolts
. its about harmonics as much as anything ... plates dont always break,, sometimes the through bolts also sheer off
using two different diameter or material metals will give the engine resistance to two different harmonic frequencies that could be destructive to either bolt or engine plate
these goopy kits allow you this twin harmonic dampening , take the least material out , have threads to stretch at only one end , and address the front plate issue with thread purchase deeper into the front plate
all at minimal cost and only requires a drill press and care
other tricks include rubber sleeving or silicone bonding the middle of the normal through bolts
- something mazda found necessary in competition when they where breaking through bolts
12-25-13, 02:06 PM
#20
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yep same Turblown stud kit I have.
However they didn't save my last rear iron. Note to self Never buy another Aeromotive 340 fuel pump again.
This was post 440hp dyno run when my pump #2 failed.
However they didn't save my last rear iron. Note to self Never buy another Aeromotive 340 fuel pump again.
This was post 440hp dyno run when my pump #2 failed.
12-26-13, 08:19 PM
#23
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The iron was a thin cast s5. I love the studs. They seem so much more precise when torquing. My next step is implementing some fail safes into my current setup.
That 440 was done on a ball bearing 60-1 at 16psi. I had reliably been running that for about a year before the pump failed.
That 440 was done on a ball bearing 60-1 at 16psi. I had reliably been running that for about a year before the pump failed.
12-27-13, 02:29 PM
#24
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I make my own dowels out of 4140 chrome alloy bar and go full length rather than using original mazda dowels and have got engines well over 500hp with no issues at all, I think the datalogit drag car here in New Zealand also uses a similarly doweled engine and they are running low 7s on the 1/4 mile so must be around 1000hp mark
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