There are quite a number of threads deidicated to the BB turbo conversion on the european forum so it may be best if you go have a read and reach your own conclusion on it.

www.lancerregister.com

my attention was first drawn by this thread

http://www.lancerregister.com//showt...ferrerid=97871

but do read all the relevant BB turbo threads as its informative

A point to consider is that a dyno sheet will show you at what rpm the boost or power is building but what it does not show is the time taken to reach that rpm.

A faster spooling turbo may not just mean that higher boost is schieved at lower rpm but that your run through the rpm range is in fact quicker as well.

 

Your point to consider has me confused because unless you are reving out of gear there is a direct mechanical link between mph and engine rpm. Since it requires power to achive mph it stands to reason that more power at a given rpm will accelerate the car faster at that point in the power band. I'm sorry but could you clarify your point.

 

Well, dun qoute me on this cos I have absolutely no formal training on this just enthusiasm (sp?). But I would believe the fact that you have less inertia to overcome means you build torque faster which means you accelerate faster.

Sorry if I cannot give a better explanation, its easier to understand when you sit in the car cos then it all makes sense :P

Maybe you can shoot a mail to Dave Gammon on the Lancer Register as he is most helpful and much better placed to answer your q's

 

I think his point was that you have to consider not only steady-state response, but also transient response.

For example, if you snap the throttle plate open, with a "laggier" turbo it will take longer to reach the the steady-state value of vehicle and engine speed than if you had an equally efficient, but less "laggy" turbo. The power would of course build up faster with the less "laggy" turbo and allow you to accelerate to the steady-state speeds more quickly.

 

dont forget its TORQUE that does the accelerating, not power!!!!!!

Chris.

 

I did get that bit right :P
I wanna lotsa torque starting down low

 

In a sense this is true, but...

Power is nothing other than the product of torque and rotational rate (angular velocity if you prefer).

You are right that at a given engine speed, "excess torque," i.e. torque available beyond what is required to keep the car at steady-state for that engine speed, is what will determine the maximum acceleration rate.

Of course what boost does is increase torque, it's the rotational speed of the engine that yields the associated power number. So to add to my previous example, a faster-spooling turbo would in fact build power faster because it would build torque faster.

 

Torque and WHP are both needed to accelerate. One would not work well with the other.


Toorque is the only power felt, this is true. NONE of yoou have ever felt HP, it is made up so us common man can understand.

You engine makes torque, thats it, the RATE in WHICH the TORQUE is APPLIED to the wheels is the measure of WHP.


Smaller turbos give a HUGE torque spike to get the car up and moving.. Look at the rally cars, they make less then 300WHP but like 450 FP of torq @ 2500 RPMS< probably because they hahve no lag due to the Anti Lag setup.

 

OK, I'm not trying to just be contentious here, but let's be clear. Of course power and torque are integral to one-another. As I said, power is the product of torque and angular velocity. The only way torque is made is by spinning a shaft (crankshaft, which is connected to the rest of the drivetrain). One does not exist without the other. It looks like you are pretty much in agreement with this with the third sentence quoted above.

However, to say HP is made up is false. Your engine power is directly consumed by friction with the ground, fluid (air) drag, AC, etc. If you are doing a top speed run and in top gear you have not reached redline, but you have reached the car's terminal velocity, it means you need more power to go any faster (chiefly to fight drag).

You can go back and look at textbook physics definitions of Energy, Work, and Power if you think this is "made up". Even if you just consider the units of these physical quantities, it will be pretty illustrative.

And finally, in case anyone is curious, two big reasons why we specifically look at torque and power both: gearing and vehicle speed. Gearing alters the split of power between its two components: torque and angular velocity. The wheels see torque=(gear ratio)*(engine torque) and angular velocity=(engine speed)/(gear ratio). As the vehicle goes up in speed, reaches redline, and has to go faster, the second term (ang. vel.) has to increase, which means gear ratio has to decrease. So you see how these terms are all related...

Probably less due to anti-lag than due to sizing the turbo to deliver boost early and choke out at higher engine speeds. You'd see a similar effect if you mounted a GT25 to an Evo.

 

you will find that they use similar to stock sized turbos. the old Cosworth boys did in fact use a T25 (old Garrett turbo) which gave them very good spool up/ lag. the thing you have to remember on a WRC/Group A car is that they have a 34mm air restricter on the inlet of the turbo! this maens that you cap the volume of air you can pass though there no mater what the rpms of engine or turbo are! so what the teams do is to run the the at the maximum flow rate through the restrictor at all rpm. this means they run very high boost preures at low rpm so they get huge torque but the torque tappers off quickly. this is the reason that most driver will sort shift (changing gear about 4-5K) as they will be quickly running out of torque (and thus accelerating slower).

Chris.

 

I recently ported, polished, and ceramic coated the factory exhaust manifold and O2 housing (turbo dump). It definately helped the turbo spool faster and increased throttle response. I would still like a ball bearing center section though. Here is the link:
http://users2.ev1.net/~subaru/evo_web/evo_exhaust.htm

 

EvoEight - That is some superb work! That is clean, more durable to maintain that clean look, ups the performance, and hopefully increases longevity as well. Top Notch!

 

That is very, very nice!

l8r)

 

EVO400 Ti turbo will hit the US market place very soon !!!!! PLEASE EMAIL ME FOR APPLICATIONS ! PLEASE ALSO NOTE ALL TURBOS ARE SPECED TO THE ENGINE THEY ARE USED ON SO THERE IS NOT A STANDARD SPEC TURBO !!! WE DEAL WITH PEOPLE EXPECTING THE FASTEST SPOOLING HARDEST REVING TURBOS SO PROPER MATCHING IS A MUST !

EVO400 GROUP BUY COMING SOON !!!!!! EVO400 lets torque !!!!!

evo400.com

 

Went to the EVO400 website. Not much works except for the link to MLR. We Americans want pictures, testimonials, hp measurements, dyno charts, etc. Would love to see info, but it's hard to access. Thanks.