Stavros

I never said it was directed at me so dont get all arsey at me you mongol, but the fact is the engines compund charged, and like i already explained in an earlier post on that page, that means it dont matter what boost the turbos are running, the boost is miles higher once it hits the engine, more than the sum of the turbo and supercharger boost seperately would be if added together.

And no, sequential turbos dont do that, they just boost like any other twin turbos do (ie how you explained), as they not a sealed unit like if a turbo blew thru another turbo or a supercharger.

RaVeR

Any videos of this car I bet it sounds the nuts

Thrush

iTrader: (1)

Define "arsey" please.... I don't see anywhere in my post that I came across as arsey.....

col cos1

iTrader: (5)

are the t2`s on a fiesta rs turbo the same as fitted to the turbo technics sierra??also my old twin turbo`d xr4x4`s turbos didint sit the same as this,i was mounted upwards and one downwards

dovboy

i dont know anyone who thinks you get 7+7=14 psi(to the engine) from two turbos

i was under the impresion that 7psi went to three cylinders and 7psi to the other three.am i wrong?

please dont argue boys as i find this compound charging shit very interesting!

am i right in thinking that the two turbo's feed a closed charger,ie say...7+7psi feeds inclosed charger which compresses already compressed air . eg lets say 14x4 =46psi?

Stavros

they feed into a common inlet, so its not added, they just share the work of creating the boost, whatever level it is.
i agree tho, gotta be a bit spaccy to think its 7x2 and cant imagine many do, not outside special school anyhow.

a turbo or two feeding an enclosed charger is the same, so they share the effort still, so say 7psi, but its multiplied to some extent (again, id need to find my notes, i forget) by the charger, its not just 7psi plus 7 from the charger or whatnot. But its not 7x7 either, as thats mental.

Pretty sure its never an exact science, but you can get a rough guess.

Basically run your charger at whatever rpm you feel is safe, set your actuator on your turbo to whatever boost you want to run, and thats it, as long as the charger on its own couldnt run more boost than you want to run combined, its fine.
All it means is the turbo is doing more or less work, depending what the charger can do on its own.

So you get a ton less backpressure than you would at the same boost if it was the turbo on its own.

GARETH T

i still dont think its ideal though steve!

fireman01

you guys are even losing me now!lol,the combined psi should be 30,only running about half that the now,but i do agree that running this setup puts less strain on the turbos,the actuators are too small,this is why i need a new electronic boost controller

Stavros

in what way?

nothings ideal, but its the easy way to get the most drivability from massive turbos on small cars.

seems random/pointless on a 4litre running twin T2s tho, as the only bonus you getting there is a lot less backpressure for the turbo size and power, rather than the drivability thing as on a 4litre itd spool from nowt anyhow.

without using things like ALS which is not a thing you can use 24/7, i cant think of a better way to get the drivability with a small engine running huge power, even VNT turbos etc dont come close.

GARETH T

dont like the idea of having three power sapping devices strapped to the engine! i do believe that a gate switch over set-up could work, but the switch over point would need alot of development to get it work right!

Rs1

iTrader: (1)

I remember it when it was in the yellow thing, spoke to the lad briefly at a local cruise, i'm sure he said it was 350hp but he ran upto 200hp of nitrous will still falls way short of the 700hp figure. Ran at york and elvington alot and blew up regular as clockwork and forever chucking the charger belts off.

Stavros

the switch over point is pointless on a pressurised charger setup IMO, as half the advantage is far less backpressure, well to the point where the boost is always far far higher than the backpressure, and would mean as soon as the charger stops working the turbo has to work miles n miles harder, massivley increasing backpressure and losing compressor efficiency.

And as the charger is doing most the work (as its multiplying the turbos boost, not just adding a few itself) there would be an enourmous drop in power no matter how carefully you engineered in the switchover too.

If the turbo didnt pressurise the charger then i could see how a switchover could work, but then you missing out on one of the big advantages of twincharging, but its commonly done this way too, dunno why.

running a supercharger saps power, but so does exhaust turbine backpressure to a similar amount.

i know of an aussie guy who has done all the testing and measuring, even in direct comparison (on the same engine) to simply supercharging, simply turboing it, using a VNT turbo, twin charging it with and without a bypass (you need a charger bypass, but only off throttle and at light throttle), and twin charging it so they run paralell rather than in series.

obv pressuring the charger means higher charge temps than usual, but nothings perfect.

GARETH T

the turbo exhaust housing will always be a problem,,, your still trying to flow alot of gas through a small housing

Mr Orange

My mate took the photos that you see of the car, with the "cruisescotland" logo on the bottom,

aint ever seen it personally tho, so i cant comment on spec or power or whatever,

mate wouldnt know much either, gave him a shot of my 1.2 clio to drive round a carpark an he nearly crashed it, but says he can drive a 4.2 V8 s-type jag with 300bhp fine

correct me if im wrong, but both the jag an my clio have a round thing infront of the drivers seat coming out from the dash, turning this gives the same effect in both cars wont it???

Stavros

Hence why you would normally run massive turbos with massive exhaust housings.
And running the charger enables that with total drivability.

Theres a Calias VL Turbo in Oz running a RB30 bottomend, a RB25 head, and a GT40 turbo with a 1.36a/r exhaust housing.
With turbo on its own it creates no meaningful power till 6000rpm.
With the charger (jag XKR one IIRC) running about 3psi (if not pressurised) it comes on full boost by about 2500rpm.

You will see it in person when you help me set the S13 up once i finish twincharging it, i got all the main bits, inc a supercharger and a faaaar too big turbo for the engine, lol (mounting the supercharger and sorting the belt pullies is the issue i have).

dovboy

the charger does sapp power but as long as you gain more than you lose then this should not be a consideration surely?

GARETH T

so 700 BHP with t2 exhaust housing? would be like running a mg mini 1" exhaust on the car

mk2rstaff

i was gonna say good choice in alloys as thats what i got in audi tt anthracite

Brigsy

My thoughts exactly, on my r5gtt with the same exhaust housing the power falls off after 5500rpm

When i owned the car on only the twin turbo setup, the power dropped off after 5000rpm, even with a wild cam fitted, good torque low down that was about it...

xr2i-carl

Stavros

there 2 of them tho remember, and IIRC the thing also has twin external wastegates, and "T2" housing is as vague as T3 really, IIRC T2 flange is same as T25/T28 like a lot of nissans etc and there are housings with that flange that happily flow well over 350bhp a pop.

i still dont think 700bhp or even 500bhp tho.

col cos1

iTrader: (5)

dalsey says its got twin t25 on it now

Mark V8

iTrader: (2)

I very much doubt even a fully modified set of 12V V6 heads could flow anywhere close to 700 bhp no matter how many turbos you bolted on

Mark

stevieturbo

I seen the Cortina at York a couple of years ago, and was gobsmacked....

IMO, the 12x terminals in a relatively light car, 4wd would suggest maybe 350bhp at best.

From what I seen, every single modification to that engine, was strangled by each other. So much work was done, and almost every bit of it, seemed to be a restriction.

2 incredibly small turbos, on a big engine, trying to blow into a big blower, then being strangled by miniscule and poor flowing intercooler plumbing, then strangled again by tiny exhausts/turbines ( and not forgetting the airflow meters too )

IMO, if it had been left normally aspirated, with the NOS it was also using, and some decent exhausts, at least the 4.0 engine would have been allowed to breathe, instead of being strangled, and IMO would have performed better.

mark

350 bhp tops

dident think a 2.9 could be bord out that much

http://www.fordpower-uk.co.uk/index.php?showtopic=2031

RWD_cossie_wil

iTrader: (9)

Garath, you are right, it's just the same way a jet engine works ,

you can compare this set up , the twin turbo and supercharger on the car engine to a gas turbine engine compressor.

I.e say there is a 2 stage centrifugal compresser( a basic gas turbine engine, 2 impellor wheels mounted on a common shaft, like a turbo wih 2 front wheels),

say each stage has a pressure ratio of 3:1. The first stage will produce 3psi from 1psi input, (the turbos on the car engine) that 3psi travells to the 2nd stage of the compresser in the gas turbine (the supercharger in the car engine) , and that 3psi gets compressed AGAIN by a factor of 3:1, to make 9psi so coming out of the second stage of the compresor (the supercharger in the cars engine) we now have 9psi from a 1psi input

Obviously if the numbers are changed to higher values you will see a much bigger difference, so using 4psi on a 3:1 pressure ratio in a two stage compressor will give you 12psi after the first stage, and 36psi after the second stage. The only problems are obvioulsly that theroey does not match practice, due to mechanical losses dues to heat/ friction etc, but its still a very good way of getting a big pressure raise with much less effort

I bet most people don't realize they have got a basic gas turbine engine minus the combustion chamber on the side of thier YB

stevieturbo

gas turbine, and pressure ratios theorys dont mean shit, if the engine doesnt have the ability to flow any air through it.

RWD_cossie_wil

iTrader: (9)

it was a bit about how compound charging works, not argueing about the car

MWF

I think when Ian Walley owned the engine he was pretty open about how hard it was to get running right.

I don't know why people bother trying to get big power out of the V6's really, especially anyone building for the strip.

Mike Rainbird

iTrader: (3)

Ignoring ALL that, the fact that he is claiming titanium gearbox internals makes me disbelieve ANYTHING further typed or posted after that point .

lead_foot

iTrader: (1)

Why did he just not just a decient V8? V6's are a waste of time if you can fit a V8 in the same gap.

Anonymous

cos its a demo car, one v6 that comes with a sierra as standard, bored out to fuck, with one supercharger and 2 turbos looks alot better as a demo car than a v8 in a car that never came with a v8.

Fil

explorer 4.0 block?

GARETH T

cause i am

col cos1

iTrader: (5)

i would say more than 350bhp like,turbo technics conversion can see 280bhp on 2.9 let alone 4.0,and 200bhp of nos????????????????

stevieturbo

It was also bolted to Ford 4x4 running gear....doing that with a V8 adds a lot of hassle.


Although the original builder seems to have went to a lot of hassle to choke the engine to death instead.

I see little reason why a 4.0 V6 engine, in simple single or twin turbo form, couldnt easily see upwards of 500bhp if built properly ( nevermind the nos )

If built wrongly.....well....see pics

Dan

Different!

The Geordie Funster

Started to read this thread and didnt have a clue about how twin turbo set up etc worked, happy to say now im at the end its still as clear as mud to me

DOVBOY 14x4 does not make 46 mate im sure it was 56 when i learnt how to count.