Doing some searches I found it could be possible to use an engine brace instead of (or in addition to) adding extra dowel pins to the engine.
Any truth to this?

 

when doing what? for mnore power?

 

Yeah-more power.

 

well if you are talking something you run on the street you won't need any pinning. But if you are building a motor from the ground up I would say use a 89-91 block because they seem to be stronger than 87-88.

 

I'm rebuilding my S4. The dowel hole under the oil filter is cracked. Most likely because I'm putting alot of power to the wheels.
So I definitely need to do something and from what I've read, there may be some other options instead of (or in addition to) upgrading to the S5 rear iron.
Any ideas?

 

dont let the hampsters escape.

 

"Most likely because I'm putting alot of power to the wheels."

whats your mods and setup where you think your power broke this

 

never mind I see from your orginal post. I would have to say with a 550/720 combo and a hybrid turbo I don't think to many people have needed to pin the block. This fuel combo is good for about 300rwhp. Now if you are leaning out and pinging you could crack the block. What type of boost are you running with water injection?

 

10 lbs at low boost. 18 lbs at high boost. At high boost intake temps peak at 35 degrees C.

 

Unless your doing 600 hp I doubt you'll need dowels.

At least one guy here is running 500hp and it is pretty stock for reinforcement.

 

Well, I'd REALLY like to agree with you 'cause I really don't want to have to go thru all that, but on the other hand, after I go thru the trouble of putting my engine back together I don't want to have to redo the whole thing.
I'd rather be safe than sorry.

 

If you wanna go bulletproof you may wanna take a look at the Xtreme stud kit from http://www.xtremerotaries.com/

 

I would bet that the crack int the end plate has nothing to do with the amount of power you are making. It was either a result of a lean condition or a vapour lock. Most likely leaned it out and blew it up. If you replace it with a new iron and have a good tune that should never happen again.

 

Don't think so. Apex seals, side seals, corner seals - all engine internals are about as perfect as you could expect (except for 1 of the coolant seals which is why I'm rebuilding it). -- and you really need to be looking to catch that cracked dowel (I almost missed it).
Dunno much about vapor lock, so I guess that could be a possibility.

Regardless, back to my original question which hasn't been answered yet .. does anyone know anything about alternatives to dowel pinning? Maybe engine brace or something like that?

 

That dowel cracks under detonation, if the apex seals don't go, that dowels the part that does next. Your setup simply doesn't support 18psi (like you said you ran at high boost), which would explain it. Use a reinforced S5 TII iron (you have to make sure it has the reinforcement, not all had it), and tune the thing properly or at least provide enough fuel for what you're throwing at it, and it won't break. Otherwise, you'll lose your apex seals/etc next time around.

 

Quick question that may or may not be off topic...
is it possible to detonate when your intake temps are 35 degs C at hi boost?

Also .. does anyone know anything about alternatives to dowel pinning? Maybe engine brace or something like that?

 

It's possible to detonate at any temp, it's a combination of lack of fuel and the temp of the air @ the intake manifolds (which would be a LOT higher than that). The alternatives are getting a reinforced iron (such as the s5 TII's), or simply tuning it properly. An engine brace isn't going to help it any.

 

35 Degrees C huh........... Hmmmmmmmm at 18 PSI of boost.... no FMIC listed in your mods... HMMMMMM

I'm having real trouble believing that.........

You say your running water injection.......

Is your Air temperature sensor located AFTER your water injection nozzel??? in which case, you are seeing the cooling effect of the water evaporating on the temperature probe rather than the actual charge temperature..

The biggest benifit of water injection is to cool the interior surfaces in the motor, thus preventing pre-detonation of the fuel air mixture before the spark plug ignites it...

550's, 720's and an SAFC are a recipie for disaster at 18PSI....

Rather than dowel pinning..... I think you need to look at other options, like better fuel management.... at 18 PSI, a properly tuned rotary has the potential to pump out 400 hp.... you don't have the fuel capacity for that, even with the water injection.

 

Dumping lots of extra fuel is only 1 of many methods to eliminate detonation. The added fuel serves the same purpose as added water or alcohol or huge IC's etc, etc. 'Tuning properly' is a relative term that varies from state to state, car to car and leadfoot to leadfoot.
But I don't want to get into a lengthy discussion about the pros and cons of WI or tuning.
The engine shows no signs of detonation.
Maybe an engine brace or upgraded tension bolts won't help at all, maybe it will. I'll make that decision when I get more info on the question I asked..
..Does anyone know anything about alternatives to dowel pinning? Maybe engine brace or something like that?

 

i think cryo-treating might help alittle also. dunno

 

"i think cryo-treating might help alittle also. dunno"

No. I think you will get most people to agree why you cracked the block is you are running 550/720 combo at 18lbs of boost. This will crack the weaker s4 block without tuning. You just don't have enuff fuel for 18lbs safely. You need larger secondaries and a standalone ems system for that type of boost on pump gas. 18lbs on pump and a AFC2 will cost you a engine ever time.

 

we are answering your question. We are saying you dont need extra dowel pins, you just need a better tune and fuel set up.

 

I forgot who it was that managed to make 5xxwhp on stock ports... And also, not too long ago, kevin landers(sp?) posted that a guy broke the rear dowel slot and the apex seals and everything else was still intact.... Maybe you ran lean pinged and cracked it, who knows. But dowell is definately not needed with your setup. Like others have said, its better to use that money to get better fuel mods.

 

I don't know how many respsonses are needed to convince, but you running 18 psi on a hybrid is just plain foolish even with WI and if you had enough fuel. Not only will that turbo NOT support that kinda boost safely on a 13b ported or not, but your not running enough fuel. Your housing cracked because of detonation or you got a bad casting period. Your cracked housing is NOT a result of making too much power. I bet your not making much if any power more at 18 psi then at 15. your just thrashing the air and heating it up loosing density there by loosing any extra power by higher psi. Its not always high intake temps or lack of fuel that can detonate either. Running that much boost and trying to squeze all the exhaust through a tiny *** stock turbine and turbine housing will hold *** LOADS of heat withen the engine chambers. Your options are. 1: lower boost to 15 psi and nhave enough fuel for it (and I'll bet your making the same power as you did at 18 and 15 psi on a hybrid is borderline) 2: Get a stronger s5 housing. 3: a stud kit as someone already pointed out by http://www.xtremerotaries.com/ or Guru motor sports. 4: Dowl the engine, which is not nessary as everyone pointed out till your making over 450~500 Whp. #2,3, and 4 are not band-aids for bad tunning.

~Mike................

 

PM Dave (guitarjunkie28), i remember seeing that he made a post about engine bracing as an alternative to (or in addition to) dowel pinning.