Turbo knowlege required

[za - sti]

can anyone assist, I am trying to compare the VF35 and the VF28

the 35 has a P15 housing which i understand is small and is restrictive. Can anyone advise what is used on the VF28

cheers

za

[AlanG]

P18 AFAIK. VF23 has P18 also. VF22 has P20.

[za - sti]

thanks Alan, moving onto a 2.5 motor - not looking for big power and really have no cash for a new turbo. Was going to use the 35 as it spools quickly. I know this sometime suffers from boost creep but in sprinting/hills never in 4th or 5th - well not intentionally!

was wondering if swapping the housing from the VF28 would make a better combination or not

regards

za

[za - sti]

thats brill gordy although i thought the VF34 is the one from the RA and the VF35 from Sti 8

if not i got a bargain!

cheers

za

[drb5]

Hey up Za! Going for 2.5, tis a nice motor, but i'd consider a larger turbo tbh.

20G on this one i have at the mo, is more than capable and is more robust than the equivilent VF turbo. The spool is surprisingly quick and makes for a very capable car.

 

Mine will be hopefully fully mapped by the end of next weekend, so if you want, we can meet up and you can see what it's like? I think it'll sway your mind. []

[drb5]

My words may not be up to much, if it is the brand new scoob your thinking about, but it will show the way it can spool up, if the same mods are used...

[za - sti]

Hi Dave, no not thinking about buying a new sti. My car is minus an engine and it is much cheaper to get an 2.5USAsti block than rebuild a 2.0l

In doing so I am aware that the VF35 that I have is not the best suited and was wondered what safe power i could get without changing the turbo, etc. If i move up to a 20G, should also get FMIC, 3inch exhaust, bigger injectors, etc, etc, etc.

what ECU are you running?

cheers

za

[fai17]

The VF 35 do indeed have a fanastic spool time but lacks top and power.

ZA...It depends how much you are paying for to rebuild the 2.0L and how much you are paying for 2.5 STI block.

I would have thought it would be cheaper to rebuild the 2.0L.

I do prefer 2.0L as the 2.5L is slower revving.

[drb5]

Peter, you sure about that spool time?! []

 

Gotcha Alex! Indeed you may as well consider the 2.5, as a rebuild defo CAN cost the same, on the 2 litre. I'm on the PFC, but if your still on the GEMS, it might be worth having a wee chat to AlanG about that area, as he's been runing his 2.5 for some time now and has changed his mind a bit in regards to ECU's.

Obviously i have a couple things that may very well help spool, but myself coming from the RA which is general, like lightening when it spools, this is really not that much difference. I've been only running 0.5 bar till it's fully mapped and it's amazing how quick it builds up. Depends on cams/heads(which you don't have to worry about) and headers, after the turbo, but apart from that, it isn't a slow spooler at all.

I'm running Tomei 740's, GT Spec headers, APS Cold Air Kit with custom Samco intake, APS front mount, STi5 ported heads/cams, Revolution 3 inch zorst and of course the 20G and it's expected to make an easy 350/350, repeat AN EASY 350/350. All on plain Optimax and 1.3 bar. Figures don't speak how nice a car to drive it is though.

Just so you know, if in the future you had to rebuild the 2.5, remember pistons and rods etc are pretty much the same price as 2 or 2.2 litre stuff, so it isn't exactly an expensive unit. Only downfall is you don't have a high redline, but most peeps i talk to, say they don't take the revs to the top before a gear change anyway.

[za - sti]

fai17/dave

the car is for sprints/hillclimbs so top end power is of little use. what is required is quick pull through the gears and instant throttle responce.

my thinking is that with the 2.5 and VF35, I will have good low down torque, quick throttle and spool but will be crap on the straight at Knockhill! The sprints/hillclimbs (with the execption of KH) are all 3rd gear max for me, max speed prob 85ish on most of the tracks. This car is rarely going to be flat out in 4th/5th gear. the 'lack' of revving doesnt bother me as you should be really changing beforehand as there is no more power coming, my shift light is at 6.2K

in terms of the engine rebuild, pistons alone are approx. 600-800 plus fitting cost. USA 2.5sti short block 1300-1500

I am still running standard intercooler, air filter box and injectors, 2.5 inch exhaust, water injection, up-rate fuel reg/fuel pump, VF35 looking for about 330/330 from the 2.5 with this set up which I dont think is unrealistic although the injectors will be maxed out and am concerned about in-cylinder heat from running a small turbo hard.

cheers

za

[drb5]

I think your main concern as in mods, with the 2.5, will be the intercooler . IMHO i would have changed it before now, for using the car the way you do. I know top mount is great for added spool, but a good mapper should be able minimise the lag due to a front mount. Wouldn't worry much about the zorst, as it won't be holding you back too much, that it can't be done later on. Maybe get some largerinjectors too though.

Certainly you should be getting a good air filter, but as you don't have a MAF to worry about, that's on your side! []