Well time to start again i think(track car)

[Grant Monkhouse]

Im going to use v-power in the car and I reLly want to rink WI as I have seen so many peoples proofs of how good it is and also on the thread you just pointed me towards he has shown one of his rotors from racing a car for a yearrunning meth injection and it was nearly perfectly clean. No carbon build up which is the biggest detriment to rotaries dying

[turbotoaster]

please dont tell me you paid for your turbo from the uk, dare i ask how much it cost.

also you shouldnt have gone for the a single scroll, its been proven even by mazda that twin scroll housings not only help with spool but actually help flow more at the top end over a single scroll equivalent.

your spec says your rear turbine wheel is actually 73mm and the housing is .88 ......which is the smallest turbine housing you can fit

if this was a low boost track car i could maybe agree, but for a drag car or looking to run a decent amount of boost id change it before you map it.

if you had ordered it from the US you could have had the 1.00 housing and £640 delivered to your door.

the rear turbine housing has a 4 inch V BAND on the rear so you will need a 4inch downpipe, the longer it stays 4in the more power you can potentially make.

a turbo works by pressure differencial, the larger that is, the easier it is to flow and more power can be produced my increasing the overall engine VE.

i wouldnt bother is a BOV, i dont run them.

[Grant Monkhouse]

73 mm is just under 3" so exhaust will be three not 4". 100mm is 4"

Where are you getting the s400 for 500 quid? Won\'t you have to pay I
Port duty and tax on top of that?

[turbotoaster]

73mm is the size of the exhaust wheel, its not the size of the turbine housing outlet, trust me i know.

its $725 delivered to my door from the US, so actually £445 but i added extra to £500 to cover for anything.

Ive never paid tax on anything ever ordered from the US

[Mattie]

73mm is the size of the exhaust wheel, its not the size of the turbine housing outlet, trust me i know.

73mm is the exducer of the turbine wheel, which when referring to turbine wheels is the internal diameter of the wheel. The inducer (referred to as OD above and given in inches) is 3.14" which is about 80mm by my reckoning. So the size of the exhaust wheel is actually 80mm which is a good size. Remember, inducers and exducers are reversed when talking about compressors and turbines and follow the direction of flow.

Agree that the housing might be a bit conservative though.

[turbotoaster]

very true mattie, i know the difference between them etc, but just focused on the smaller size as this was something grant mentioned, didnt want to get to technical yet, but your right, i should have clarified it a bit further with the inducer size to help explain.

im suprised since its a drag rx4 he went for a small turbo unless he was using a stock port 13bt or 12a for example

[Grant Monkhouse]

Small? I was advised to go for something GT40 sized as anything else would betokened small. I was told that it\'s best to go for something of this size to start with as the car will be a handful to get used to. Remember this is an old car, not an FD. Once I have got use to driving this car/engine/turbo setup I have been advised that a GT42 would work well with the car but would be very top end crazy fast. This will be the fastest car I have ever owned, currently my FD is the fastest.

Som you can see where imaging with the car, I think getting used to a single turbo car is going to be interesting in itself. My turbo housing is something I will worry about once I can get  the car doing what I want, admittedly I may get huge more amounts of mid rang from the turbo but it\'s not just going to stop producing power at point X is it?

As this is a car that I will be keeping for some time my plans are to eventually get a 20B in there running a GT 42 or 45 sized turbo. At the moment it\'s the beginning of learning something forself. One reason why I bought the data loggit software and box.

The only person I get to talk to regularly about turbos and rotories is my dad and it just isn\'t something he knows lots about. If it was 2 stroke engines then he is the best as he has forgotten more about 2strokes than most know.

I know there are websites for asking questions but az I find a lot of the experts that do share info don\'t tend to let all the info out there as it is there big secret. Good for their business but bad fir me trying to learn things.

So starting with this small turbo is a good starting point don\'t you think? Especially if I\'m aiming to have something with the capability of making up to 800Hp in the future?

[Grant Monkhouse]

Right just been in touch about my turbo. Getting turbine housing swapped for twin scroll. And have the choice of .91 and 1.00 housing. Seen as though I have gone for twin scroll now for earlier spool might aswell get the .91 for earlier spool than the 1.00?

And it is all free of charge. Bonus.

[turbotoaster]

ok ill try and break it down for you simply to help.

your concerned that the car will be to fast with a big turbo on.

You have a wastegate spring you can change to give you the boost and in turn the power you require...once you get used to that power you can increase the boost.

Why go through the hassle of changing turbos when you wanna go faster, get the right turbo to begin with, it will save you time, money and hassle.

starting with a small turbo in my opinion is false economy, either permanently decide what your power output is or cover both angles so you can increase.


also that turbo isnt capable of 800bhp on a rotary, thats on a piston engine your thinking of, maxed out your looking no more than 600bhp.

im sure in theory that would be fast enough for most people but then your talking about 20b which says it wont be.

personally if you havent already bought the turbo get a s475 with a 83mm exhaust and 1.00a/r turbine housing

if you have already ordered the s366 turbo get the 1.00, do not have the .91, its to small

[Grant Monkhouse]

right i have got my turbo out and measured it to prove a point, complete with pictures and tape measure for proof of size of the turbine exit.

 


 
 
 
As you can see the V band outer edge does even measure 4", 3 and 3/4 is what i see.
 
I know that we males can get away with telling females that things are bigger than what they actually are but when talking inches between males theres no bull, simple facts, i know im being very .....y here but sometimes you can be wrong Lee.
 
Thanks for the advice you give but your not right about everything

[turbotoaster]

i wasnt calling you a liar dude.

you told me the turbo you had bought was a 177281.

Ive got the BW 2011 catalog in front of me now and for that model number it states that the rear turbine size for that is 4.21in, hear is a picture to show you.


I assumed with you saying you can get it changed for free you hadnt recieved it yet and got the information wrong, so my apologies, guess the catalogue must be incorrect or they have nicked a turbine housing from a different model, saying that it doesnt list single entry housings as thats old tech now.


with that in mind i think everyone will agree you need to change your rear housing to a larger 1.00 twin entry with 4in exit

and mate your not being ....y about it, i was in the wrong


p.s right click image and click view image to see it full size to view in detail better(though it might be my crappy firefox)

[Grant Monkhouse]

ahh yes thats one of the 2 sheets i have got, i will apologise about the measurement as it does say 4.21 on the drawing, So we were both right.
 
Getting the turbine housing changed 2moro hopefully.
 
Bit strange them not giving me the sheet with single scroll info on?? I will double tripple check they hive me the right size housing.
 
Was going to go up to 4" after the downpipe but might aswell be the whole thing

[turbotoaster]

exhaust gas has its most \'energy\' when its under pressure and high temperature.

When you increase the temperature of a gas you increase its size....it expands.

now when the exhaust gas leaves the turbine housing it is at one of its hottest temps(manifold runner is highest)

because of the temp it is at its largest area(m3) per gravimetric weight, so to reduce restriction you want the largest pipe you can fit on the there.

Anyone who tells you different is wrong(for n/a thats different)

so you want the 4inch now, as the exhaust gas travels along the pipes is starts to cool, which means contraction(shrinks) and loses its energy and slows down, if at this point you want to decrease this pipe size then thats fine....obviously to a point, you couldnt downgrade it to 2inch for example.

basically, you want the biggest you can while the exhaust gas is the hottest, try and maintain a 4inch the full length if you can, downgrade to 3-3.5 as late as possible to minimise the effects.


For reference im gonna run a 5in downpipe to a 4in exhaust, also v band it at the point just before it goes 4in so i can fit a 5in side pipe popping out behind the front wheel for pod......saves weight and maybe make a touch more power


oh yeh, if you want the full pdf file with all the turbos from BW this year let me know, its got all the spec and compressor maps of the EFR series to have a read if you like

[AtomicRex]

With the volumetric size of the pipe, yes the bigger is better, but you ideally want the air to be travelling at as close to the speed of sound...it cant travel any faster.  So if by going up to a 5" pipe you are miles away from that it is purely unnecessary.  So by increasing the temp you either increase its volume or speed.

[Grant Monkhouse]

I understand what you have mentioned, think we have discussed it before. The way I see an exhaust gas working is from a little lesson I learned at high school about pressure "a gas or liquid that is in an area of higher pressure will always want to go to an area of lower pressure" to equal itself out. So in theory a staged exhaust, smaller to big, would be good for keeping the velocity up whilst releasing the pressure.

Maybe a couple of variable restrictor in an exhaust would be good? Help buil the pressure to maintain velocity.

I read a person findings on na exhaust systems on his v8, and he found that he could reduce the lengths of the runners and overall length of the exhaust by essentially tricking the exhaust, basically he took the headers to a box where this box acted as though it had vented the exhaust to atmosphere, then had a large diameter exhaust to the rear.

I wish I knew where I read it as it was brilliant for understanding na exhaust systems. I think he benefitted at low rpms more than high. Some of this stuff could be applied over to us turbo guys as if you can achieve great power without them then I beleive the benefits with a turbo would be even greater than just bolting a huge turbo on there.