Anyone who thinks the material aluminum, as used in an engine block, is the limiting factor in an engine's ability to handle boost is on crack. Half you guys just have no clue what you're talking about. An engine is designed or not designed to handle boost in it's initial design phase. Aluminum is only a limiting factor if the engine was not designed for forced induction. Every high output turbocharged F1 engine in the late 80's and on used an aluminum block. You know, when they were making 1,500hp out of 1.5L aluminum motors.

I'd like a real technical explanation as to why the f*ck the #3 cylinder would blow because a Subaru's block is aluminum???? It wouldn't have ANYTHING to do with say oil and coolant passage routing, placement of exhaust tubing, airflow and fuel distribution into that cylinder, etc...I know nothing about the STi's idiosyncrasies but I'd be willing to bet my cancerous left ******** that aluminum has nothing to do with it IF the block was designed correctly. Now if there's some sealing issue between say the block and head, that's a design issue and not a materials issue. There's a big difference between the two. The housings on my turbocharged third gen RX7 are aluminum and I guarantee they see substantially higher EGT's for a longer period of time than their pistons counterparts. But I'm ranting, so I digress....

 

oooh but back on topic, didn't Porsche send off the last 944Turbo S with 300hp? And if I remember the last series of the Esprit S4 has around 320hp or so? The special production cars non-withstanding, the Evo holds it's own pretty well! Technology is wonderful, ain't it?

 

IIRC the S4 was a 2.2 "Chargecooled" four that put out 264 horse but had the feature of "overboosting" close to 300 when conditions were right.

And Porsche did have a 944 turbo S with 250 horse, I think they only imported a few hundred. My friend had a stage 3 Autothority chipped 88' 944 turbo that hauled!!

 

Yeah but there was some sort of "supersport" model that was still in existence when the V8 Esprit was "king" and I thought it was north of 300hp? I'll have to google it...regardless, I'm sure it wasn't a third as reliable as the Evo. Yeah, a bit of sarcasm there even though I've had no issues

 

Ah found it...http://www.lotusespritworld.com/EModels/300.html

I guess the higher hp models were all V8's.

 

no i say s2k since it's a NA engine

 

"n/a K20A's from Honda easily put out 230-240 NA whp with bolt ons in EF/EG/EK chassis"

uhhh no... which o ne u talkin about? the one thats 160 at the crank or 200? lol u are not getting 240 whp out of a ******* acura. i owned one. i even owned the civic si ep3 too. good luck. thats the numbers they run with a turbo! lol
and also what does the chassis have to do with whp? i dont get it....
are you saying a stripped hatch with a bigger motor will rip? yeah it will.

 

143 hp per liter is pretty good......

 

I think the new Audi A3 2.0T has potential. Even though it's turbo charged and weights 500 pounds more than the S2000, it has an EPA rating of 25city/30hwy compare to S2000 with 20city/26hwy.

Audi A3 200hp/207tq (chipped it will be around 250hp/275tq)
S2000 240hp/162tq

But there's nothing like the Evo.

 

it only happens on the US spec STI's that get built up using the stock block. the melting point of Aluminum is 660 deg C vs Iron @ 1563 deg C. Al is also only 1/3 the density of Iron as well which is another inhibiting factor when dealing with pressure. if an Al block is designed for forced induction it does well but not AS well as it's Iron counterpart. so if EGT's hang out in the 900+ deg C range on a stock block STI, what do you think is happening? they stuck the turbo right next to the block behind cylinder 3 (pass. side) retarded design IMO. people have to build up there STI blocks to prevent this from occuring. the 2007 STI is rumored with a H6 option which shouldn't have this problem. the RX7 rotary is a true testament to Al designed well, but they also blow up easy if you aren't careful. at least they're cheap to fix...

as far as Honda goes, i truly believe they have the capability to put out a turbo monster if they choose but they are on the environmental ride right now. u have to admit that the NSX motor was worthless once u added FI to it. i've seen plenty blow up. now if they would have designed it as a turbo car, it would be more valuble then the Supras are right now.

 

I'm pretty certain that you're wrong here. Actually I'm certain. The 1.5L 4cyl era of Formula 1 engines were all cast iron. BMW was infamous for making the most power, but they also had the most dramatic failures, most of them being, blocks splitting in half and some crumbling to pieces, the BMW engines were actually using production based blocks and they were most certainly cast iron.

Aluminum is very much a limiting factor in boosted applications. Anyone remember when the LS1's first started to see high boost? They would pull the head bolts right out of the block. That's why you see lots of guys running the iron LSx blocks out of the trucks. It's one of the reasons why the SR20 was never able to come close to the HP figures for the 4G63.

 

Actually, the BMW 1.5L turbo that made 1400+ used a standard iron block out of high mileage 318i's IIRC. I remember reading about them and how they wanted older blocks that had lots of heat cycles to help strengthen the structure.

 

The Honda V6 twin turbo engines that came next and were the most dominant and most reliable engines of the period were also cast iron blocks.

 

i don't think anyone here is arguing the point that aluminum is weaker and have a lower melting point than iron, every one should that. but, to say that aluminum is the limiting factor when it comes to force induction is wrong. most auto manufacture don't design there engines with the intention for the consumers to throw a turbo in there and increase the power by 200%, they are design just to handle the power output from the factory with some safety margin. some engines have a larger safety margin than others like the engines from the evo, skyline and supra, all of which are incidentally turbo from the factory. if aluminum can't handle boost, why do these engines still use aluminum heads and pistons, they are also a part of the combustion chambers aren't they? aren't current CART, IRL and the 6000+ hp Top Fuel engines (all of which are force induction) are made of aluminum? what about outlaw class 4-cylinder 7 sec. drag cars that push 1200+ whp on built factory aluminum blocks. like i said before, the blocks are aluminum but the cylinder sleeves are steel. aluminum cars aren't any less safe then steel cars, it's all in the design and engineering.

 

I did a bit of research on the BMW engine and it is in fact an iron block cast in the late 50's believe it or not. In the late 80's BMW cast some new blocks to solve the splitting issue. Perhaps it just wasn't technically feasible to cast aluminum blocks necessary to withstand the forces back then...maybe the casting techniques weren't refined enough....but it's certainly not a problem now as everything's aluminum. Unfortunately restrictors keep the peak power down but I wouldn't be surprised if cylinder pressure was similar on modern engines. And the VG Nissan guys do not seem to be having trouble making insane hp levels with their aluminum V6's. We just don't see more aluminum blocks due to complexity of manufacturing not only the block but the entire package that bolts to it.