minispeed
Turbo Mini Forums

just had a nice chat to rob at mini speed , he was extremely helpfull and patient with all my questions ,and gave me a 10 % discount cos he decided that i must have been on minifinity!!.very nice chap .got all my bits for the conversion from 29.5 to 31 mm exhausts in stainless for less than i thought it was going to cost.
regards robert

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

minispeed in byfleet?

the people are nice but are you sure they should be in Good Garages?

a friend of mine drove away and the wheel fell off!

i've been waiting over a year for one part. good job i'm not i a rush to fit it!

On 1st of Dec, 2006 at 01:44pm robert said:
just had a nice chat to rob at mini speed , he was extremely helpfull and patient with all my questions ,and gave me a 10 % discount cos he decided that i must have been on minifinity!!.very nice chap .got all my bits for the conversion from 29.5 to 31 mm exhausts in stainless for less than i thought it was going to cost.
regards robert

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

urgh is right !!

please .axel , the details of your sphinctal dimensions are unneccesary !!
made me laugh though.

Edited by robert on 1st Dec, 2006.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

in fact after a quick look the hole in the gt17 ,after the wastegate , is approx 20 percent bigger than that in the t3 !!! so it would appear the t3 hole is , in fact far closer to the dimension of your suchard blowpipe.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

It was a serious question, although I could have made a better comparison

I thought I read fab state that it was only 0.7 sq ins?

That's what I would expect given the small turbine inducer diameter and the A/R ratio.

But if you can see it is bigger than the T3, you are probably working along the right lines.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

that has to be the first time i have heard of minispeed spoken in good light on a forum

but fair play to them if they helped you out robert

okey doky , i didnt realize it was a serious q ,

i measured it and the t3 was 29mm by 18.8mm and the 17 was 28.8mm by 24.44mm,

this is measuring each housing just past the wastegate flap area,where the pipe gets to a true volute .
so thats 545.2 mm for the t3 area and 703.9 mm for the 17 ,,,,so i was wrong ,its 29 percent bigger at that point ,suprised me ,but i guess thats how come the saab can be chipped up to 235.bhp ..


bear in mind that each hole is not really a rectangle , its more like a halfway house between a circle and a rectangle , for some reason the word romboid jumps to mind but its prob wrong ,lol

the a/r is .25 on the t3 ,and .47 on the 17 . incidentaly , i measured a .48 a/r on a t3 i have ,and it was 771.75mm area.

of course all this is only really comparable if the volute tapers at the same rate ,is the same distance from the centre (radius) the inlet slot around the blades is the same width ,and the wheel the same dimensions and so on , but its interesting anyway .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

So why does it start boost at 1400rpm?

The gas has less velocity at that point and is acting on a shorter radius, hence is putting less energy into the shaft.

You would expect it to be less responsive than the T3.

I think you need to have another measure. If your area is 1.0 sq in ish, then the radius must be 2" for an A/R of 0.5. That sounds a bit high for a 44mm dia turbine.

Or am I missing something?

We've gone off track on this thread again!

Edited by Paul S on 1st Dec, 2006.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

this is way before the shaft and wheel entry slots axel , the point where the area is measured for the a/r is not necessarily where i measured it i imagine thats way down the bore , i think it boosts at the rpm it does because of the package . ,and i think this turbo has a better wheel design on both the turbine and the impeller , and its also a lot lot lighter rotational mass ,etcetc ,blah blah blah .
lol
regards
robert

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

i was just about to pick you up on that .7 axel .lololol

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

[quote=robert,1st of Dec, 2006 at 08:27pm],


bear in mind that each hole is not really a rectangle , its more like a halfway house between a circle and a rectangle , for some reason the word romboid jumps to mind but its prob wrong ,lol

quote]
this was meant to say dont take the measurements as gospel , just as good as i could get in a couple of seconds , the measurements i have stuck here are just a simple rectangle .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

My guess is that it actually gets much smaller before it hits the turbine.

Hence, the velocity must be very high at that point to generate the boost. To get the velocity at the nozzle, you need pressure in the manifold. Bigger exhaust valves will have doubtful value if your engine is limited by exhaust pressure rather than flow.

The reason I asked the question is because I am trying to determine if the GT17 would be good for my 998 and have been doing some research. I think it may well be a step up from the T2 at least.

PS - I bought some stuff from Minispeed a few weeks ago. I dont normally but they were the only people with the kit I wanted. No problems.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM