hoskib

iTrader: (1)

hi,
after some great advice and info about the dawes device i'm left with a niggling doubt,does running a higher than standard boost do any long term damage to the engine/turbo etc.?
i'm only asking as i intend to keep the car for a good few years yet and don't want to run into problems later on. sorry to be a big girl cos the dawes sounds great,it just seems to do so much for your car for only £50 that there must be a downside somewhere?!

StickyMicky

if u use anything harder then designed for it will break earlier

if u leave your heater blower on full whack constantly it wont last as long as one thats slowly

The_Judge

As long as you also purchase a Knocklink, AFR, and boost gauge, you should be able to run a few more psi's of boost relatively safely. Just don't get bitten by the bug...

Regards,

Ade.

Lars

My MY1999 has now done 107.000 km and has a Dawes fitted since 25.000km NO problem up to now. I run 1.05 bar and rest of engine is standard.

crispyduck

iTrader: (1)

I've had about 2.5 years experience of the Dawes MBC and been impressed. As already stated, don't be tempted to go over anything around 0.1 bar less than the factory fuel cut, on the coldest day of the year!) unless you really know what you are doing. Also the equipment already mentioned allows you to see if this is safe. High octane fuel is also a must if you start increasing boost.

There has been concerns about high boost at part throttle. High boost at part (well any) throttle is due to the characteristics of the device itself, as it allows as much boost all the time until it reaches the boost level you have set. I have never really found out any good information on this, so as long as the car is running within 'normal' operating parameters things should be fine. I assume this problem has bitten people who are running boost higher than factory fuel cut with no other mods, and then I can see why you would have problems (lean running - bang!). This is why people seem to go for an ECUTEK to 'improve' the 'efficency' of the fuel map in the cars original ECU. Obviously, a custom map can be used with or without a Dawes, you will gain in either.

Another characteristic of the Dawes is that the hotter it gets the more it tappers of boost at the high end of the rev-range. Most electronic boost controllers, including our standard ones, do this as a safety measure. Obviously via electronics, they do this in a much more controlled fashion - its just nice the Dawes luckily does something similar.

In summary, Dawes is good for 10,15,20% increases in boost, which nearly equates to the same increase in BHP in addition to LOADS more torque through out the rev range. It is the additional torque that makes it such a joy. Any more and you should be taking (other) things a little more seriously. This is where any advice from me runs out, and the serious boys step-in.

[Editted to say "coldest day of the year"!]

[Edited by stevecrisp - 10/23/2003 2:49:08 PM]

hoskib

iTrader: (1)

cheers guys,top info! bit of a no brainer really!
special thanks to stevecrisp for explaining it in a way even i can understand! (not easy!)while on the subject you say about setting to 0.1 bar under the fuel cut,what is the fuel cut in psi on a uk MY99 scooby please?
cheers

john banks

17.6 PSI sustained for about a second. However it may det at this level... suggest go for 16 PSI unless you use octane booster and/or have a knocklink.

Remember that torque gains are at best in proportion to the increase in absolute not relative pressure, so an increase of "10%" in boost from 1.0 to 1.1 bar in the midrange represents at most a 5% not 10% increase in torque (absolute pressure from 2.0 to 2.1 bar). Even then the ignition will retard and it will run a bit richer, plus the turbo is less efficient on both compressor and exhaust sides at higher boost. So the gain in torque is probably more like 3-4% from such an increase.

On the standard TD04 the gains are even less in terms of power, an increase from 0.8 to 1.0 bar at 6000 RPM doesn't give anything like the gain you might imagine.

It is still good and worth doing, the butt dyno tends to suggest the increase is more because of the boost delivery of the Dawes rather than the actual torque or power increase. The butt dyno is far more sensitive to rate of change of torque than torque itself. Don't be tempted to read the boost gauge as a power meter, as often you can run more boost and get less power.

Also in assessing potential increases in power, consider the increase in boost AT THE RPM AT WHICH YOU GET PEAK POWER, not in the midrange. It is nonsense on a TD04 to quote that you get say 270 BHP at 1.2 bar when in fact at peak power you are probably running only 1.0 bar because it tapers off as the exhaust manifold pressure blows open the wastegate against the fairly weak 0.5 bar actuator. Often it is worth giving up some boost at the top end on a small turbo and exchanging it for timing. This is what they do from the factory. Some is there for free lunch power, but it is easy to overdo it on the boost.

yhe chod

mr john banks is it fair to say you will get better power and torque more reliably and safely from a remap of ecu[ppp ecu remapped or replaced with ecutec] than using dawes[cost aside] specifically a ppp uk99 with decat exhaust

john banks

I used both together with success, but on a 99/00 the decat PPP is pretty good indeed. You can't really compare the methods though... one is a boost controller and one is a fuel/timing/boost remap. if the fuel and timing are suitable for higher boost then a boost controller can work nicely alone.