nick_scott

does anyone have any advice on turbo upgrades? which are good or show the most gains?or have any experience with their own?

cheers

Danny Fisher

Nick, what model is it you have? UK, STi or WRX?

Also what year is it?

Dan

Scott J Davies

I have been looking into this extensively myself for my beauty, and have decided to stick with the VF28 already on my car and instead have it tweaked by Turbo Dynamics, nice.

This will give me more response, more power and a stronger turbo, all without the lag of a large daddy turbo. Its the way forward and cheaper to boot.

cwal1

What's involved in tweaking an existing turbo in order to gain increased response, power and strength but with reduced lag ?

Chris.

nick_scott

i have got a myoo uk. I have done some mods to it already, intake etc. Larger intercooler.

ideas?

quattro

Unfortunately, I am not in a position to give direct advice, but can try and give general guidelines.

Bigger turbo means more air means more power at same boost levels (and even more at higher boost levels) means more lag means trouble with driveability unless handled correctly.

For UK cars VF23 is a good replacement for the wretched TD04s and, combined with a good downpipe and the rest of the exhaust as well as at least an efficient panel filter if not an induction kit, will give easily noticeable improvements across the rev range. Unofortunately, none of this will make enough sense if the standard JECS ecu is left to do what it did prior to changes, so some solution in this respect will bring enromous rewards (various options: chips, piggybacks, semi-ecus, ecus, high-end ecus. I am again deliberately leaving aside that part of the topic untouched).

For imported cars it is much easier. WRXs already come with VF22s so all you need to do is make it sing the song you want and engine management components combined with "input and output" will make the VF22 lose most of its low-down lag and give other benefits.

For ultimate results, as one member mentioned, there are specially designed "hybrid" turbochargers which are as good as dangerous unless you have a suitable specification for your particular application on your particular car and its state of tuning. There is much more to this than just bolting the front end (turbine) from one VF models and rear end (exhaust, wastegate) from another one. So, be careful what you do there as it takes very little to miss the results you want. Good people like Turbo Dynamics will do their utmost to follow your wishes how you want your turbo modified, but they do not have your car and cannot guarantee the outcome. To give an example: small variations around the wastegate valve can make huge differences in how the turbo and your car behaves. But, if done properly, results are beautiful and you can even have a very big turbo moving a hell of a lot of air with very little lag and unexepectedly good pick-up ( spooling) at the bottom. Needless to say, mapping, ecus, exhaust, intake, dump valves, etc, etc. count more and more the further you go and very small changes in the overall system configuration can make very big differences in end results.

Hope this helps.

q.

steve McCulloch

I have the sti5 and had the VF28 on originally - =switched to a VF22 - the difference was noticable above 3500 revs - the only problem is the amount of lag - its a real pain - all other cars will blow you away until you get on full boost!

The VF22 blew up within about 2 months of having it on - I reckon it was a design fault - so switched back to the VF28 - difference amazing - felt like I had a faster car again - if you are not interested in outright power keep the VF28

however I wanted more power - so I got another VF22 and sent it to Turbo dynamics for a MD195 conversion.

The lag is terrible (partly mapped out by the link) but once it comes on full boost above 4000 rpm the difference in performance is astonishing - although the performance band seems quite low - around 4000-5000 is the only really noticable band range - saying that its better than the VF22 - much better IMHO

If you like a fast car keep with the VF28 though - you might get a little hacked off with a bigger turbo having to change down gears to get the performance you want!

Plus a modded VF22 is about £1300 - plus change - including oil and filter - so your looking at around £1500 for a change and probably a day off work getting it sorted at the likes of Powerstation

R19KET

I wish people would choose a turbo based on their driving style, and what they ultimately want to achieve.

We all know that a bigger turbo, whilst being capable of producing more power, will be more laggy. The skill of the turbo hybrider is to limit the amount of increased lag, whilst improving the amount of air flow.

It's nigh on impossible to make a turbo with increased air flow, AND reduce the lag.

A good map will certainly minimise lag, but it's still relative to what it can do to a smaller turbo.

I also think that people get too hung up on comparing the boost level from one turbo to another, and equating it with performance.

If your car is much quicker running 1.4bar with a big turbo, than it is with a small turbo, it stands to reason that it's producing more power, at a given boost level. Therefore, even though a bigger turbo may only be able to produce eg. 1bar @ 3500, compared to a smaller turbo producing 1.2bar, power is probably very similar.

Ok, at low rev's lag is far more noticable, but is changing down a gear such a pain.......not when you cruise past most other cars on the road, or should I say track

Mark.

nick_scott

thanks guys,

so well my idea now is to try a boost controller and run around 1.2bar, which i suppose is max boost for a myoo. What will help to reduce lag though? If i do get a bigger turbo, what else would help to reduce lag, i have no map tuners where i live so it is goin to be based upon mechanics.

Bob Rawle

For a UK car one of the best upgrade's turbo wise is the IHI VF23, coupled with a fully programmable ecu this will provide significant performance with minimal lag increase.

Steve, don't forget you still have cat's ... still something to gain lower down once that's not in the way.

With my hybrid turbo and twin dump down pipe plus 3" exhaust I still get 1 bar boost by 3500 rpm. Thats just as good as with a VF22.

Go with Marks post as well, its horses for courses and big power at high revs does not equate to a quick car, depends what you want, its the torque that counts.

One thing, a bigger turbo will move more air for any given boost value ... don't get too hung up on pressure, you could have a turbo producing 2 bar yet actually deliver next to no air flow, its not all about the numbers but the air flow at the pressure. Doubling the density of one litre of air will not generate as much power (read torque) as doubling the density of 1.3 litres of air. (given that the same AFR is maintained)

BTW Mark is the re-heat working yet ?

Nick, if you are going to run that boost on the standard ecu make sure that you establish that the fueling is ok. You are also getting very close to the boost cut dependant on ecu tolerance. the engine will stand it but ecu limits may not ... be sure to run 97 ron fuel as well.

Bob

steve McCulloch

Bob - I think the rust on the BPM exhaust will give me no choice soon but to change!!


Mark - if its other Scoobys (including UK) you dont 'cruise' past as you have to much lag - I do notice the overall power hike - just wish there was some way of designing a turbo that had very little lag - Motech??

Sam Elassar

nick
the best thing it to see other cars with the modifications your want to get and see if this achieves what you are after. are you in the UK ?

from personal experience i have a MY99 with a VF23 and possum link running 18psi, and i am very pleased with the result and i would not go back to just the standard turbo ( unless of course i have to). the car is laggier no doubt but it is a lot quicker overall. next step will be a front mounted intercooler soon, what intercooler have you got ?

sam

R19KET

Steve,

next time you're at Bob's for a Link re-tune, ask him to give your driving style a re-tune too then come and tell me you can't drive around the lag.

Mark.

nick_scott

sam, i have an aps intercooler. It runs well nice and powerful. No great increase in power but it is more drivable. One question though, how does a blow off valve help/ work?