Trying to get a idea on how much I can get on my S4 block.

What's the highest known HP that someone has achieved on a S4 block without any studding?

 

well my s4 block (turbo) i got 420hp to the wheels with a minor port job and some upgrades...60-1 turbo 1000 cc primary injectors, 1600 secondary injectors, fuel pump 3 in exhaust and a lt10 microtech stand alone. oh at 20lb of boost

 

What type of fuel, and how long have you been running that ?

 

You need to ask for other details? Is this S4 block running stock S4 rotors? Is the block doweled, or added side plates, bottom plates, etc..alot can be added to a stock block. I would ask for specifics. Like a stock oem block limits, or something along those lines..Basically your hunting @ the zoo and you got the deer in the corner..lol Your not going to get what your looking to know, from what your asking.

 

I saw a video of J-Rat making 401 on a stock S4.

 

I just need to know whp on motors without any internal strengthening. I don't care about porting etc. etc. etc.

 

S4 block "without studding" is what he asked. And adding sideplates? Bottom plates? What do you mean? A pan brace?? Trust me, a pan brace won't stop the upper rear dowel land from busting out of its pantyhose.

Generally speaking, I know an S5 block won't take kindly to much more then 520-550whp for extended periods......depending on the castings......but I honestly have no idea where the limit would be for a few glory pulls.

My best (safe) guess with an S4 block for a *reliable* (and repeatable) amount of power would be 480ish before things start dropping off the engine.

 

So, what are the S5 guys doing when they want more than 550 whp? Studding? RE? REW?

 

The reason, I ask. Is, because I have a stock S4 block and I want to have a little fun this winter before I get silly next spring.

Just wanted to get an idea of what kind I power I can play with before breaking something. It's getting tuned by Kan in November so tuning should be spot on.

 

Any and all of the above

Just have him go as far as he's comfortable with. But you're in a different boat being a booze fueled cruiser......so you might get a little further before hitting any problems being that everything is going to be a little cooler, and a little less likely to detonate.

 

I think BDC has made well over 400 on ported S4 blocks, but dont quote me on that.

 

You are correct. Completely stock motor with turbo and an alcohol system.

 

430 rwhp on tmic with alky iirc. bdc setup

 

Yeah rat made 400 but he eventually cracked the rear iron in the common top oil spot.

He went to S5 irons which have thicker casting in that area.

 

I've heard about a guy in Australia who made over 700 on an unpinned S4 block in a drag car. Never saw the car or got any other info but I found it interesting because it supports my theory that the older blocks can hold high power just fine. I don't think the issue is power with the engine blocks and I don't think that whatever "reinforcement" that was done on sucessive engines has anything to do with power se; I think it has to do with knock resiliency.

If you look real close, you'll notice that the only thing that holds the housings laterally together is the cast iron dowel lands on the three irons. When the rotor housings either swell or want to deflect laterally against the iron, they drag the dowel pins with them and the iron lands on the housings are what are having to hold these pins inplace. In short, the iron dowel lands are holding all of the force of combustion. When the engine experiences engine knock that produces severe spikes in pressure, it's my opinion that those quick blasts inside the chambers act alot like trying to smack the side of the housing with a hammer and that's what ultimately breaks those lands. Notice the direction that the lands on the irons crack.

B

 

Are you still seeing people break the dowel landing as frequent now that most are using WI?

 

^^ I sort of see what you're saying, but why is it then that the s4 motors break irons so much more frequently then? Are the s5 motors more knock resilient due to the spark plug locations moving or something?

 

IMO its somewhat like what Brian is saying, the force of a knock event pushing out on the irons - but there's certainly a point (not exactly sure where, and its definetly not written in stone) where the pure dynamic force of a clean combustion is too much for the dowel lands to hold at all - knock or not. The explosion *is* what's making the power. More power, larger explosion, more force on the block......

Certainly the thicker castings are more resiliant, and I also believe the engine mount placement plays a role as if you examine the history of them, each major engine revision brought the mounts further back....

 

To your question, it seems that 400ish seems to be the number above which motors destroy themselves more frequently for whatever reason. fwiw

 

The lands on the 89 and post irons (along with brand-new housings of today) are thicker. They're meatier. It makes sense therefore that they can take alot more shock load. I just don't know how much.

As far as the spark plug location, I am not sure. It does something with changing the effect of the flame front but I don't know. Crispeed may be able to answer that.

B

 

I don't think it's a straight power thing although I'm not a guy who makes 700hp on an S4 block. I think it's the force of knock and the spikes of extremely high pressures (that are far above and beyond normal combustion events) that are doing this. I picture it as a difference between hanging your body on the end of a breaker bar w/ a socket that's trying to break a bolt loose vs using a hammer on that same breaker bar. Perhaps someone with more physics knowledge can illuminate this concept a bit more.

B

 

Anymore insight?

 

I posted in that other thread about 400whp. Maybe I have a factory freak, but I could not kill my s4 irons no matter how many times I detonated them.

 

He is making 520hp on the dyno run he showed me at sevenstock for a stock S4 block.

 

^it's S5 irons now.