chief-long-shin

Hi all

Dont really know jack about turbos etc but i do have a question.
I have a standard 94 WRX. After seeing how quick the evo's get going i was keen as to how to get the scoobs moving quicker.

What sort of mods do you need to get the car on boost quicker so i'm not counting

1 / 1000

2 / 1000

3 / 1000


BOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOST......


Cheers all.


BTW, not looking to spend super bucks on a 400bhp block as i have a 40 mile commute daily.

m493

do away with cats mate one of the first and best mods im told

chief-long-shin

they have 2 dont they, you think there would be a difference with one removed?

What implications would this have on emissions do you think. Have standard exhaust at min but looking for a nur spec

m493

dont hold me to all this but i think uk models have 2 cats imports have 1 .i think if you leave 1 in it should be ok or get the sports cat for the one on the down pipe and just have a straight through center section and i believe that will pass emissions


mike

hall84

taking both cats out will make a very big difference, turbo will spool faster and will sound awsome, especialy with a nur spec system! as for the emissions.......get friendly with an MOT tester

j

chief-long-shin

i thought that would be the case.

do you need to remap once you've done exhaust and cat.

Anyother suggestions on zorst, i keep seeing hayward and scott and afterburner vortex come up on here but i feel blitz will offer best gains for that mod alone.....

am i talking crap?

ian10

remap would make quicker spool up, you don't necessary need a remap though with a decatted system i suggest decat your car as suggested and try it

harvey

iTrader: (48)

Performance proven, 3" exhaust and open neck downpipe. No Cats.
Wrap the down pipe with quality exhaust wrap. eg DEI from Nimbus or API.
Ported O/E headers and up-pipe. Exhaust wrapped.
When the above are done, consider wrapping the turbo exhaust section.

chief-long-shin

Could you explain what this does and how it works. I understand the decats = more power and no mot cert however i dont understand the exhaust wrapping.

Cheers.

DRINKYWRX

The wrap helps keep heat in the pipes, which makes them flow quicker which in turn will spool the turbo faster.

A bleed valve (dawes device) will help a lot to bring the boost in early, no need to go crazy with it, full decat should have your td05 on a bar by 3300rpm

Roojai

If you want the easiest and quickest and cheapest method then the dawes device would be it. As drinkyWRX says, you don't need to turn up the boost much, just set it for around 14psi or 14.5psi and you should be fine, even with your cat still in place. You need a boost gauge to set it.

I think you may be happy with the dawes device alone, but a decat does improve things.

You only have one cat, in the down pipe, - the other cat-looking thing is a resonator box. It's not an "difficult" job to change the downpipe cat for a decat pipe but it takes a while to remove all the bits to get to it and you may have difficulty with siezed nuts in the turbo. You need a good ratchet set to get to the nuts under the turbo.

Mo

As already stated, a Dawes will be the most cost effective upgrade.

chief-long-shin

CAn anyone hook me up with a link or anymore info on how these bleed valves work and what the implications of their use are.

Cheers.

Roojai

I am sure if you search on scoobynet or on google you could probably find quite a lot. there are a load for sale on ebay at present.

I will go into the basics for your benefit:

They are not a bleed valve as they do not 'bleed' air from the system like some valves on other cars do. All they are is a spring closed valve that runs on a small pipe from the manifold to the turbo waste-gate actuator. Normally the ball and spring closes the valve so that the tube is sealed but when the manifold pressure gets to a certain level, say 14psi, then the valve lets the air through the pipe which opens the the wastegate, preventing the boost from climbing higher.

They are good because the do not let any air through until the boost target is reached, so the wastegate is kept shut which means that boost builds quickly. electonic boost controllers and the standard boost control solenoid lets some air through to the waste gate even before the boost target is reached (in an on -off pattern known as the duty cycle) and this means full boost is reached more gradually. A mapper can map the cars ECU to bring in the boost harder and quicker by changing the duty cycles but of course this is much more expensive than a Dawes device.

They are also good because the will always open the wastegate at the preset level which prevents boost creep (over boosting). Bleed valves and boost solenoids may not open sufficiently in certain conditons resulting in over boost.

The third reason they are good is that they are so simple there is not much to go wrong and they are easy to set.

A problem with them is the fact that if you can set the boost target way too high and you will reach fuel cut or even damage your engine. You need to be careful with them and use a boost gauge starting from low boost levels slowly building up to the desired boost setting.

scoobfan

It increases exhaust gas velocity allowing the turbo to spool quicker.

It also has the added benefit of reducing under bonnet tempratures
which in turn reduces charge tempratures, which helps increase boost!

So it's a good idea.

Rob

New_scooby_04

iTrader: (4)

I wouldn't put a Dawes device on a UK car, let alone a 12 year old Jap import!!

Making the exhaust system more efficient is the best way of increasing spool up. I'd listen to Harvey!

I'd also be thinking about changes to the ECU to ensure that the car continues to run safely and can be run on UK fuel with no OB. If you've not already got one, I'd also recommend a Knock link.

NS04

GrahamG

Where the best place for Heat Wrap?

Cheers
G.

Lord Bass

try www.demon-tweeks.co.uk

Mo

Care to say why you wouldn't?

Here's 4 reasons why I would........
A Dawes will provide excellent boost control
A Dawes will provide the best spool for your set-up
A Dawes can be fitted in minutes
A Dawes costs peanuts

Wurzel

iTrader: (1)

Change the crank pulley to a perrin or something equally light and your engine will spool up alot quicker.

OEM pulley = 2500g
Perrin = 500g

Plus I would never use a dawes device either, reason being is it overides all the safety checking of the boost from the ECU so if you have a problem the first thing you know is when your engine goes bang.

there is a reason why a Dawes device is so cheap and proper boost management systems are so expensive you work out the reasons for yourself!

I have a3 port boost solenoid mapped into my car to control boost.

Try talking to Bob Rawle about why you shouldn't fit a dawes device before making your decision.

Graz

Sorry but that is simply not true either. The ECU with still be reading the MAP sensor and if it sees the boost go over a certain level it will stop fuelling (fuel cut). So the ECU safety measure is still in place. Of course you can fiddle with this as well using a fuel cut defender, however you really do need to know what you're doing then + have the relevant instrumentation - boost guage, KnockLink and air/fuel ratio meter (preferably wideband) at a minimum.

Dawes on its own is quite an effective mod provided you don't go silly with the boost and if you do you'll only keep hitting the fuel cut making the car undrivable. Of course supporting instrumentation is always a good idea as mentioned just to keep an eye on things and ensure good fuelling / no det.

Graz

Oh yeah back to the original question - how to make the turbo spool quicker.....

Anti-lag

Will certainly spool quickly but you'll need a new one every few thousand miles

Wurzel

iTrader: (1)

Ok I stand corrected but still would not use one, but as it happens I do not need one now anyway

KenS55STI

I used to have a 94 wrx and found that fitting the scoobysport H&S 3" to 2.5" open neck downpipe and a straight through 2.5" centre and scooysport 2.5" H&S backbox made a massive difference. I liked it so much I kept it for my next car.

It always used to be said that the 2.5" was better than the 3" for making the turbo spool up at low revs but I don't know exactly how much difference there is.

Mo

I bet if it was sold for £200 rather than £20 there'd be more interest

harvey

iTrader: (48)

For those of you considering a Dawes, try a GBE valve from AS performance.
In some applications there is a place for this mod.
Just as DRINKYWRX said, the more fluid the exhaust gas the better it flows.
Think about thick oil. Warm it up and it flows better. Same for exhaust gas.
Also think about this, your engine is only an air pump so the bigger the temperature differentials you can get between gas in and gas out, the more potential you have to develop power.