dont say search I already tried that.

I'm intersted in buying a TII, is there any major difference between the generations of TIIs? is one more reliable?

 

reliability is the same, I would say, as for the faster, I think its the differences in the twin scroll and wastegate of each of the turbos.

 

um the higher compression rotors make a big difference and it has higher boost. s5 turbo compression is 9.1 and s4 is 8.4 and s5 boost is like 7pis and s4 is only 5.5psi
i think that is about it for power differences.

most people like the look of s5 more.

 

What makes it faster? S5 ( 89-91 ) has 202HP while S4 (86-88) has 182HP. This is mainly due to higher compression rotors on the S5 and slightly higher boost levels, with a revised independant twin scroll turbo.

 

i raced a friend from a roll, he had a 90 i have a 87 same mods, but he had a lightened flywheel, and i was pulling on hi each time, but i also raced my friends FD from a 60mph roll, he had a intake and dp and i was pulling... so i think it comes down to drivers or maybe my car is a freak

 

The S5s aren't faster than S4s once there modded, in fact, because the S4 is a little lighter, plus with the lower compression(good for high boost) I would perfer it if I planed to do alot of modding. I own a S5, mostly because I found one in good shape near me first. I do think S5s looks MUCH better, and they seem to be a little more valuble, so each has their +'s and -'s

 

An S4 with S5 turbo and wastegate, S5 engine but S4 housings is the best I heard. Then do the S5 exterior. Voila 200 lbs lighter S5 TII.

The extra hp argument is an ongoing one some say S5's are faster while others say they are fatter so the extra hp is negated. Drive both and make up your own mind .

--Fritz

 

IT doesnt matter. there both good rides. whatever u get a better deal on

 

Not to mention a lightened Flywheel, better attentive ECU and larger Intake Ports.

 

So could the s5 high compression rotors be swapped into a s4 engine and come out with s5 TT numbers? How does that work, whats the difference between the s4 and s5 rotors?

 

compression, the s5 ones are also lighter,
but it isn't just the rotors that make the difference. It is alot to do the with all of the above mentioned things working in conjunction with each other.

 

Don't forget the tuned intake manifold on the S5-I think that's good for extra hp, and can be put on an S4 if you like. I've also heard the turbos and manifolds are much better units on the S5.

 

Yeah, It's the Intake Manofolds Is what I mean't earlier.

 

S4 peak boost level was 6.56 PSI

 

Zenki is 8.5:1 rotors and rated at 182hp with a boost max of 5.5psi.
Kouki is 9.0:1 rotors and rated at 200hp with a boost max of 7.5psi.
It is kinda obvious why it's faster?


-Ted

 

Ok, this boost level thing was killing me, so I searched and found this back in a past thread quoted by NZ.

 

Yep, I think the figures that Ted quoted are where the boost level falls to at redline, but max boost occurs earlier in the rev range. This is pretty typical behaviour for stock turbos on most cars.

 

S4 FC's can get fast very quickly once your start modding them. So that 20 extra hp becomes obsolete really fast.

Most ppl that have there choice of buying a s4 or a s5 in there price range that can find them would choose the s5 for many reasons.

But you have to understand that these cars respond very well to modification and that its very common to find FC's modded already. So the argument about which one is faster stock vs. stock is kinda pointless IMO.

 

You make a good point, but some of the major contributors to that extra 20hp (exhaust manifold, turbine housing, intake manifold, compression ratio) are the sorts of things that remain unchanged until you get fairly serious. This means that a modded S4 engine making the same power as a modded S5 is going to be working harder to do it, or conversely, making less power on the same boost. There are other considerations besides peak power too, like the shape of the torque curve and boost response, which will be better on an S5.

 

Also one other thing is the clutch type LSD on the S4 vs. the Torsen on the S5. Nothing to do with speed but I like the clutch type better

--Fritz

 

s5's had a viscous diff, but many do prefer the s4 clutch type to it anyway. fd's got the torsen

 

Yeah I was just looking at the Green RE Porsche/FD and the stupid torsen ended up as what I typed, I meant to write viscous, thank you for the correction Time to go drool over something else I guess. Damn these cars are so sexxxxxxxyyyy.

--Fritz