This is just a casual question, but:
Can anyone please list in broad terms what a 2.33 takes to pull together?
I do not mean an 'andyF' extreme machine, but you can take a 2.5 with stock internals, add a TDo520g, headers,Sti heads etc etc and get around 400 x 400 ish; you can take the same parts and a 'custom' 2.5 with uprated internals and push 500 x 450 ish with a twisted turbo etc.
I'm asking if you take a CDblock 2.0L/2,2 bore (is that right?) and the 2.5 crank..top it off with the heads etc off an Sti v3 and add the 20g etc as above, what advantage is that combination over my 2.0L '407' x 340 outpiy Sti v3.

God, I hope that makes some sense, so don't shout at me if not.

Graham.

 

Extra capacity, extra torque capability. Closed deck block provides strength to keep it all together when you push for high power / boost

 

I thought you and T-uk had the same 6 speed gearbox?

 

Any body know who's the cheapest for a standard 2.5L Sti short engine at the moment?.

Thanks.

 

Andy,

I don't think you're using fair comparisons, because as you know, it takes time to find the best set up for a car. My car is a good example !

Are you going back to a 2.0lt then ?


Mark.

 

LOL, my car never performed with the 2.5. IMO i did too many things in one go and suffered accordingly.

Graham (911)/Bob D, drive a proper 2.5 and see the difference it has over the 2.0l as an every day car. Truly amazing.

 

Alan, they do, but T-uk changes gear quicker, when I tried I broke it, more custom for Neil Engineering. The big difference with my car was changing from 2.0 to 2.5 with no other changes (staying with 20G) than a manifold. Should've stuck there. One problem with it though was that it was still a bit short geared and so even then didn't live up to its potential. Then the bigger turbos on the 2.5 ended up less responsive than a TD05 on a 2.0, exacerbating the ridiculous gearing further and making it more on/off, T-uk's car was faster point to point with 2.0/TD05 in the wet/twisty road than my 2.5/GT30R setup with me driving I think. Fantastic push and excitement on the GT30R but not as quick in my hands. With your greater driving experience/ability Alan, and your engine's ability to get massive torque with more safety as well as more sensible gearing it sounds like you have the right turbo and an ace setup. Still sounds a handful and a half though!

 

The 2.5 makes for a quick road car, although it does feel quicker than it actually is. Remember John, not that long ago when your 2.5 UK was quicker than my type R and that was with you driving it !

When the 2 cars were alongside or nose to tail, the 2.5 just pulled away from the 2.0 of a similar spec. On the strip or track however it would have been more even, perhaps the 2.0 may actually have had the edge if it was kept 'on the boil' fully.

 

Sounds like high, peak power would be more important for the 1/4 mile than having a big torqued mid range power plant?

I think you're gearing John probably didn't help your 2.5/GT30. As if you had run out of gear(s) (1st 4 of the 6) before the GT30 really showed it's potential maybe?

 

Although i have very limited experience amongst you all on this thread, if I strain all these opinions through a siv it seems that (for a road/hill climb car) the stock 2.5 from the States, a 20g with support mods and an Sti V3 donar engine is a strong simple package if not pushed too hard ib boost.

Hill climbing is only driving a fast country lane knowing nobody is coming the other way for about 60 seconds, so very twisty/cambered/undulating and greasy in the wet, ideal for the above engine.

Masses of torque/power switching in so to speak would be dreadful in these circumstances.

My 2L/20g etc has just slight lagg if I'm driving like a pratt and drop under the boost point, but if you can keep it over 4500 then it is a cracking engine.

I think I will have to wait for it to go pop before the wife will agree to a 2.5/box

400 bhp x 350 lbft is very average for hill climb class this year, and 450x 400 is more the target for 2006 to keep up with the 480 x 450 EVO.
I hope Pavlo can do it in his car.
Threads like this are great for novices like me. Thanks!

Graham.

 

Maybe i'm wrong in thinking this, but i would have thought, a really revvy 2 litre engine, would have been better suited to what you use it for Graham, than a mildly tuned 2.5.

 

Andy,

Some times you send me mixed messages

And then !!!

The reason some 2.5s don't shine, is IMHO because they aren't put together correctly !

UK cams, undersized turbo's, and 99.5mm bores just don't go very well together. They'll be fine for a relatively low powered car, but for people looking for more, the power will peak around 5000rpm, and then just die off, because the UK cams, small'ish turbo just can't fill the cylinders.

But look how the 2.5's go with either STi, or modified cams, and a decent turbo..........


Mark.

 

When I went up against your Type R on the same turbo Andy, I had the PAR 5 speed gearkit (which had very similar gearing to the original 5 speed UK box), and we also did try some pulls from lower revs in a higher gear. I think they were similar for top end power, but then you had the problem of running out of gears?

I do think like many that the MY06 STI gearing would be ace with a 20G, and there would be so little to do to that car to get it up to speed (fuel pump, remap, exhaust, 20G.

 

What do you mean
Johns had sti cams with a decent turbo and was properly set up. It felt VERY fast on the road but didn't produce the numbers on the strip. Alan Bells car is the same, proper spec, it feels very quick but doesn't display it on track against the clock.
Why is that ?

Andy

 

[wooden spoon] cos they both drive like wimmin? [/wooden spoon]

 

Andy,

In general terms, a car is either fast, or it isn't. If you have a quick car, and it doesn't translate onto the drag strip, has the car suddenly become slow, or do you think it may be down to the driver, or the way the car's been set up ? IIRC, Johns car was still pulling 121mph terminals, which isn't too shabby !

Remember, in my hands my car did an 11.54/128mph, in Stevens, it's now doing 10.93/132mph, and since it's been better set up, it's doing 10.41/138mph !!!

1/4 mile drag times are a very unreliable measure of a cars power, and just as much a measure of the drivers ability to launch, and change gear.

Here's a comparison of a 2.0lt v a 2.35lt. The 2.0lt has some 30bhp more power, but which would you choose to drive ?



Mark.

 

3rd time lucky !

 

My 2p's worth
I think just swapping an engine to get bigger power is sometimes a hinderence rather than a bonus.
Most people say "oh i want 400/400" so go for a 2.5, when really they wont notice much difference with 350/350 from a 2ltr (and probably wont be able to use it most of the time) so for drivability the 2ltr wins on a day to day basis
I think that people see the BHP figure as what they want, when really its the torque figure they need to be looking at, that makes the car drivable in day to day situations, so is there a need in most cases to go for a 2.5?
I also think that people look and think "bigger is better" when its not always the case.
So are people actually throwing their money away buying a 2.5 when the 2ltr they have, in 99% of the cases, do the job just as well?

Tony

 

Disagree, a car with an agressive boost curve can feel faster than it really is, the 2.35 above more than doubles its torque output within 500rpm and this gives the 'wow' effect but may not be too practical to drive !
Johns 2.5/450bhp terminal was only 2mph above Bobs 340bhp 2.0 in identical UK base cars.

The power curve you show doesn't tell the full story, the 2.0 I know for a fact went on to 8000 rpm, so if you were using the top end of the powerband as during racing then the 2.0 would be the quickest. IIRC the 2 cars these engines were fitted in done very similar 1/4 miles of mid 11's 2 years back.
For a torquey road car I'd go 2.5 but for track then I'd consider carefully before jumping in.

 

Mines a great everyday car the torque is fantastic (for me anyway) and its not that bad on track for a bugeye 12.9 1/4 , mile, 60ft 1.6 , speed109, >> and room for improvement , cheers Alan.

 

Mine was 434 BHP and had the six speed in for the 121mph terminal, and it also had A/C and about 30kg of ICE and all the tools, tyre pressures were not played with, but I agree the 2.0 gets very close indeed, not sure of Bob's spec, but I think like T-uk it is lighter. A lot must be the driver though, like wimmin as Peanuts so eloquently expresses it T-uk didn't have any trouble matching my old 2.5/GT30R setup on the road

The torque on the 2.33 plot is very impressive, but it looks like an engine dyno plot whereas I think the 2.0 is Well Lane, so might be tricky to make a direct comparison, although it is interesting.

 

Sorry John, I thought your best terminal was the day you and John H ran it with the full interior stripped out ?
So the 434bhp run was with the 20G still on there ? not the GT30R ?

Andy

 

Andy,

If you look at the original 2.0lt graph, you'll see tha it actually peaks at circa 6750rpm, and then starts to drop away. My comparison graph actually shows the 2.0lt in a better light !

I'm not talking about what a car "feels" like, my words were "If you have a quick car".

I'm not certain if it's fair to use Bob's car as a comparison, it's very much an anomaly, in as much as no one else I'm aware of, has even come close to his results, with similar power.

I'm not suggesting a 2.5lt is the only way to go, but IMHO, correctly set up, even at 350/350, it's a far more drivable car than a 2.0lt.

Mark.

 

So what determines a "quick" car then ? If racing against the clock is out due to driver differences and we can't judge based on what it "feels" like ?

Now you're talking, driveable I'll agree on but regards faster (or quicker ) hmmmmm ???

 

Andy,



I guess a more reliable reflection would be in gear rolling starts. Anything else will be distorted.




Mark.

 

Poppycock. The 2.5 gives better driveability over the 2.0, even at the same peak power levels, the reduction in lag and boost threshold combined with the increase in off boost torque makes the 2.5 much more straightforward to drive. You will I am sure see many reviews of the MY06 WRX with the 2.5 engine.

Paul

 

121 mph terminal on the 20G and the GT30R, on the 5 speed with your AP22 the 20G with NF did 124.9 mph terminal. 20G was full interior, GT30R was stripped. 20G had methanol, GT30R didn't. 434 BHP was on 20G with methanol, never dyno tested the GT30R. 20G was much easier to launch.

 

Really?
Yet its proven that the JDM 2ltr is more drivable again

Tony

 

Comparing apples with umbrellas again.

If you were to remove 2 of the cats fitted to the UK model over the JDM version, then add the twin scroll turbo of the JDM, and the emission unfriendly mapping of the JDM finished off with a 2.5 shortblock the result would be more driveability than even your precious spec C.

Paul

 

Tony,
Have you driven a 2.5 on the road?

Err.... "Day to day" I'd take a 2.5 every time

If I wanted to make silly power and go racing it every weekend, then I would have gone with a 2.33

I wanted a road car that I could take to a strip/track and play.
My old UK lump was getting tired. If the 2.5 short engine wasn't so cheap I would have had a 2.0 CDB built. It probably would have been stronger due to the forged internals, but would have struggled to get the torque of the cheap 2.5 and cost an extra 50%

Seeing as I didn't see me pushing past 400/400 the 2.5 was the best option for the road car I wanted.

I do agree people see the figures and think the 2.5 is a cheap way to do it. It is to a certain level.



Sorry I must have missed where it was proved the JDM 2.0 was a more drivable car





Now back to the bickering