x838nwy

It does and it doesn't. I agree that up to say 350-400whp the evo gives you a lot more for your money power-wise. After that the difference is more to do with the choice of tuner, parts etc.

Strange, this. I have the 6-speed on my 8MR and another 6-speed in the Sti. I don't seem to think either have it 'wrong', in fact they're both very well spaced IMO. I don't to drag racing so I can't comment on what happens on the strip, however. From my experience, the Sti gearbox has a nicer operation (I have short shifter installed). From an engineering point of view, it should also be more efficient. As I said, I don't think any difference between the two is that great but if there is any, I think the Sti has the better of the two.

Perhaps it is more to do with which you're used to. When I go from my evo to my sti, I need some time to get into the swing of things regarding shifting right and such. It doesn't take very long, but I'd imagine that if I jumped from one straight to another, I'd feel a bit iffy.

This is perhaps a result of the sti's wheelbase being shorter than the evo. In city traffic, I prefer the sti. IMO I think it will be hard for an evo to beat an sti in a gymkhana type event (both stock). As for over/understeer, IMO both understeer. The Sti (up to 05 at least) oversteers slightly on throttle while the evo kindda stays the same. To me, it's more a preferrence thing. The evo does turn sharper but to _me_ it's more nervous than the sti.

I can't comment on the turbo since mine came with a non-standard one. As you pointed out, the tmic has its advantages. With ic's there's always a trade off between cooling effect/pressure drop/transient response. The sti's philosophy seems to lean towards the last two and there are good reasons for this. The effect from cooling is rather slight compared to the adverse from the pressure drop. I've seen cars that lose hp from getting afterarket intercoolers (Carlos seems to have sufferred the same). All in all, with the stock turbo, I don't think the tmic is an issue at all. Once you want to go for bigger turbos then it's really a matter of matching up the plumbing and the turbo. Unless you're going wildly larger than stock, I'd assume the stock or an upgraded top mount will do. And this brings us to the issue of lag. Because of its setup, it is easier to get the turbo/ic sizing wrong in an sti than the evo which I suppose is why the sti is normally perceived to have more lag.

One thing for sure is that Sti's are harder to work on than evos. The system as a whole is rather unconventional and I assume that there are fewer big power tuners for the sti than the evo. I would put things like spun bearings and such down to installation errors. To be fair, evo's are very easy to work on but yet we see people with broken engines all the time.

I don't want this to spiral into another **** fight but in all seriousness I think the difference between the two is down to preferrence. I'm sure we can find subaru forums with posts saying why we should all cry and sell our evos. I posted a link on this thread a few posts back with dynos of both cars. It's interesting and shows they're pretty even. I have both and while I've modded the evo quite a lot, the sti is catless but otherwise stock.

Obviously I am not talking about big power tuning - which I don't think Carlos had in mind - and really once you get into strokers and turbo kits, it's as much to do with tuners as the car itself.

Sorry to have gone on for so long...

fromWRXtoEVO

iTrader: (18)

Noize, I love the way you expressed yourself on you last comment (last page), you really put a great comment.

X838NWY. I agree, it is the matter of choices. I am not planning on modding the STI too much. I would mostlikely will get a full exhaust, CAI and MBC. I already have a extra SMC kit waiting for install.

I just want another nice daily driver and I think the STI is a street friendly ride. I saw a couple of used 06s, I just need to throw some numbers and see if I decide on the 06 or a use 05. Either way I think I wouldn't be dissapointed.

I would mostlikely give a try with Al and see what he can do on mail in flash. I haven't heard from him on this topic yet but I would still give him the benefit of the doubt as I think he is a master of tuning.


The bigest downside on the STI is the turbo size and how far the turbo is located. Additionally the TMIC gets all the heat soak and if you decide to go FMIC you must accept that you are installing a minimum of about 10 feet of IC piping which makes the eficiency nule.

On turbo and intercooler location the Evo is a winner. Even the turbo gets cool down as you roll and you also get the heat out of the engine bay though the hood opening, we can't argue that on that aspect the Evo has a win to win situation.

On the other note never understimate the STIs, you can always slap a cheap *** VF22 for $500 and you would be surprise. Alcohol kits are also making the torque megahuge on the STIs .



Carlos

x838nwy

Carlos, here's something to whet your appetite, if you're into this sort of thing:

Prodrive (Japan) cat back for the Sti:
http://www.prodrive-japan.com/products/muffler/

^I'm getting this one (already have HKS high flow cat).

Prodrive (Japan) coilovers for the Sti:
http://www.prodrive-japan.com/products/suspension/


And cos you said you didn't want to mod it extensively:
http://www.cosworth.com/shop_range.php?typeid=42

They do pistons (obviously), cams, conrods and heads for the 2.5 and a few other things like this:

For $5,150 you get:
<LI>New Subaru EJ25 STI Engine Case
<LI>New Subaru STI Forged Crankshaft
<LI>Cosworth Forged Connecting Rods
<LI>Cosworth Forged Pistons
<LI>Cosworth High Performance Piston Rings
<LI>Cosworth Race Spec coated Tri- Metal Bearings
<LI>Balanced and Professionally assembled
Billet Crankshaft optional
It's almost worth it....

Noize

iTrader: (24)

x383nwy-

With respect, you cannot compare an awesome EJ207 powered S203 Impreza to our dumbed down US STi with its low revving EJ257. Have you actually driven a US Spec STi? Because if you have not, your comparison is magazine racing at best. If you have, then look at the evidence I'm providing below more closely.

The gear spacing issues in the STi can't be ignored. Here are gear speeds of these cars at their indicated redlines (7000rpm):

US Evo VIII 5 speed: 40,60,83,113,162
US VIII/IX 6 speed: 40,60,82,107,135,169
US STi: 37,56,76,99,138,177

In essence, not only do you have to shift the STi to 5th in the quarter mile, but you would need it road racing as well. You can get away with never using fifth in an autocross, but with our lower redline STi, you'll need it in most other professional forms of racing. If you notice, there's nearly a 40mph gear spacing hurdle, and it happens around 100mph. That's hardly nice for acceleration at all.

Moreover, almost all the Evo flashes move the rev limiter up to ~7800rpm, and this is completely safe on the stock driveline. You can't safely accomplish this with the STi, as the piston speeds would be too high, and its beyond the usable powerband of the engine anyway.


I'd need to read up more on the S203 to be sure, but doesn't it have Spec C underpinnings as the S202 did? The Spec C has nicer suspension components than the US STi.

To me, lightning fast turn in makes a car more responsive to inputs. In all the US mag comparos (now I'm the one magazine racing, LOL), the Evo almost always came out on top and is faster around even short race tracks. In the STi's defense, the Evo tires are probably better.

This is a big point where we disagree. TMICs are a total compromise compared to FMICs for pretty much everything in my book. This does not hold true for the STi because of the strange orientation the H-motor has in the engine bay. The turbo is on top, near the firewall at the passenger side. It makes it easier in this application to plumb. The reason these cars will never be front mounted from the factory is that the lag would be unbearable. The problem, though, is heat soak. With repeated hot lapping/autrocrossing, drag racing, anywhere where the car has to slow for a bit, the car will see a marked performance decrease.

I agree, but that's the fault of the manufacturer of the IC or more likely the car's owner for not selecting the unit that would work best for his application. I had an aftermarket IC, gained nothing but lag (even with tuning), and later removed it. That big core takes longer to charge!


I agree on both cars other than heat soak in hot/extreme racing conditions for the STi.

While the Evo is more forgiving, physics itself disagrees with what you are suggesting. There is just too much pre-turbo piping for any EJ motor to be anywhere near as efficient as a 4G63. With two exhaust ports on each side firing down on the EJ engines, one side has to cross completely over and meet the other two ports at a collector. You can slice it anyway you want, but that sucks for spool, and is why Subarus have tiny OEM turbochargers to make up for this. If you introduce a front mount into this equation, you better have some RPM and an anti-lag device in the Subie, because lag after upshifts is going to be very bad.


Evidence of spun rod bearings on EJ257s is too widespread for me to believe that it is due to installation effor. The failures often happen at x power level, which would suggest strength. At the shop I use, the strongest EJ blocks all have reinforced aftermarket bearings.


There are some definite advantages to the STi. I just don't think that engine performance or acceleration potential are among those.

Here's a link of lightly modded Evo and STi on the dyno. The Evo is the red graph, the STi in blue. To be fair to the STi, the Evo does have cams and cam gears (on top of what both have below), which are not nearly as easy to install on a Subaru. Still, both represent these cars with fairly light modifications and how you'll often see them in the USA. As you can see, the 16G runs away from the vf39, and the 4G63 has a lot more RPM to work with. Both are tuned and have full exhausts.

Noize

iTrader: (24)

I think there are definitely better places to go for STi tuning than Al. There are a ton of ECUtek dealers all over the US, and a custom tune is probably not too far of a drive from you.




Not really. The vf22 is a little better than vf39, but still tiny and will get destroyed by a well tuned cammed stock turbo Evo. If you want to make a difference in an STi, look to a 20G/Green/something in that class. They fit in stock location and make substantially more power than any of the popular IHI setups or their modded versions (1820, etc).

x838nwy

Noize,

There is one thing which is a little problematic to our discussion. Mainly I'm probably talking about more of the JDM 2.0L Sti and guys from the US (which makes most here!) are talking about the 2.5L. I have not driven these 2.5L machines and as such I don't know if there's any difference in gearing. [To be sure I'll see what mine does at 7k in various gears and let you know.] It would be rather strange IMO for Subaru to change gear ratios in only one gear. I can't see how they would go through all that extra effort and did something silly to the ratios.

Anyway, if we take the 7k rpm speeds as a basis and assume we shift accordigly, rpm's as we start each gear is as follows:
evo 5 speed - 4,666/5,060/5,142/4,882
evo 6 speed - 4,666/5,122/5,364/5,548/5,869
sti 6 speed - 4,625/5,157/5,373/5,021/5,458

The difference is around 500rpm. Now if you have sufficient torque at 5,000 rpm, I don't see much wrong with this and by the looks of things, it seems they've geared for it. Obviously as real-life shifts aren't instantaneous, you probably get into 5th slightly lower than 5,000rpm which might be a problem. More likely however is that often tuners aim for big hp numbers, sometimes at the expense of torque and power band. If they're not careful, this will cause problems with this particualr set.

I be fair, the S203 suspension comprises of Sti linkages and 4-step adjustable struts and Sti springs. Now this might sound like a lot but save the linkage, from the other sti's i've driven, the stock strus aren't all that different. In fact the difference between the non Bilstein evo's and the MR's is waay more pronounced. As for turning, personally, the evo's steering is quicker and lighter but its turning circle is larger and it understeers more on throttle. Nothing you can't drive around, mind.

The thing about the turbo charger, I agree that the pulmbing going toward the turbo on the sti makes it inherently disadvantaged. And this has been an area of quite intense development by subie themselves. The various incarnations of sti's over the year pretty much all have different manifolds, up pipes and down pipes which is real confusing. The upside to all this is that the path from the intake all the way to the intake mani is very short. I guess they're betting on gaining from that side of things.

With the 2.5, the situation can only improve IMO. The additional capacity should be able to offset much of the lag. Assuming of course, that Subaru North America haven't done something silly I don't see why the 2.5L if anything isn't potentially better than what I have....

One thing I suppose is that JDM sti's alone there are between 6 and 9 versions depending on who you talk to and there are versions where the are somthing silly like 3 catalytic converters in some strange places (like the up pipe) and is likely to be the case given some emission regs in the US. Again, this is nothing that cannot be overcome but might be something unique to the States and is perhaps why your sti's are a little crapper

Noize

iTrader: (24)

I tell you one thing, if still had my Subaru I'd envy you and your EJ207 like crazy. The US got ripped off IMO and Japan has the awesome engine. The 207 can rev close to 8500 with just a flash on stock internals.

x838nwy

Noize,

Sorry to dig this up again, but just remembered to look at the speedo on my Sti at 7k rpm in 6th. The needle is right at 125mph.

I couldn't remember the number you posted here (well, I've just seen it now, US Sti = 138mph) and seems quite a lot different. Unfortunately cos I didn't know then that it was different, I didn't look at it in other gears.

It would be likely that other gears are different also since if 4th is the same as the US Sti then we'd be talking about 5th gear starting at 5,566rpm if you shift from redline in 4th which does seem a little high.

This is really quite strange and I can only think that Subaru has chosen to have different gearing for the US market for reasons of mpg figures - where perhaps cars are tested at 'standard' speeds which probably just happenes to be a particularly bad point in the jdm sti's operating curve. I mean, according to the US figures, 55mph in 5th is at 2,790rpm whereas the JDM would be around 3,080rpm....