bj928

ok guys, i need educating, building a v8 twin turbo ford, 32v, 5.0 or 5.4 not sure yet, revving to 7500ish+/-, each bank will be 2.5 or 2.7, want to run higher comp ratio, maybe 9.3-9.5:1, and i hate lag, now i know bugger all about how to choose a turbo, what all the numbers mean and what makes a good turbo a good one, and a bad one bad, how do you choose what boost to run, or will this be down to which turbo, not looking for mega numbers in BHP, but want drive ability, top HP doesn't matter and i don't have a figure in mind, thought this would be a good place to ask, and maybe educate me and maybe help others out,

Adam-M

Plenty of info on this site regarding borg Warner twin scroll turbos that appear to be the best for response

bj928

i was looking at them, and thats sort of why i asked, i see turbos at well over a grand, then the BW S300 and S400 at well under a grand, why are some so much money and others cheap, i have been trying to do research, but it seems to be an info overload, need teaching in simplified terms if thats possible,

moondustka

What you want from the engine will determine what turbo you would choose. You need a HP figure in mind to start the ball rolling, peak and nominal. You also need to decide what power band is most important to you - I.e. 2-4krpm, 4-6krpm for example. Then you can choose compressor housings and exhaust housings to suit your performing preference, driveabilty etc. External wastegates aren't entirely necessary but can handle exhaust gas pressures more efficiently.

That's my brief understanding anyway..

bj928

i want the power as low as i can get it, as said i hate lag, the 5.0 would be 435hp standard and N/A, the 5.4 come supercharged from factory and are 550hp, now i know some say the ameica figures don't cross over to uk figures, so these could be higher than they would dyno in the uk, i don't really want to say a top hp figure i want, i want to more build a very drivable engine and the top line HP is what it is, the vehicle it goes in will be used for a bit of track, and drag, but also used daily when i can

Adam-M

What about using two twin scroll turbos from a spec c Impreza? There small (max hp about 360) so should spool up rapid especially on your bigger engine?

bj928

that sounds like an option, but will they be to small and run out of buff

Adam-M

Shouldn't be too bad, they rev to 8250rpm out of the box so should be spec'd with that in mind

bj928

does the size of the turbo relate to the power given depending on size of engine, ie, a turbo that produces 500hp on a 4 pot 2.0, would 2 of them on a 5.0 v8 produce less as each turbo is running a 2.5 4 pot engine not a 2.0 4 pot engine, or will they produce the same just spool a little quicker

Adam-M

I was under the impression a larger engine would make power power and spool up quicker

stevieturbo

Are you looking to buy new or used ?

And as Moon says, you really need some proper goals in mind, both for power and spool.

But if you consider most OEM turbos are on around 2.0 cars these days, and spool fast...the same turbos mounted to an older lower revving less efficient, albeit larger capacity V8 should perform in a fairly similar manner and will be readily available second hand...and if a popular platform, upgrades also readily available.

The likes of the BW's are good, but the 300's and 400's would be far far too big for what you're suggesting, even without a power goal.
Some of the smaller S200's might be a better idea.

eg

https://agpturbo.com/borg-warner-agp...-turbocharger/

But even this might be a little large depending on your goals.

Or bound to be plenty of GT28 type units out there again if you aim for something fitted to a 2.0 factory car, on your 2.5 per bank engine, they should spool very fast, and OEM's usually spool very well already.

There must be loads of TT kits in the states you could get ideas from ?

stevieturbo

A compressor is designed with a certain airflow and pressure ratio in mind.

ie a 500hp capable compressor might work superbly on a 2.0 at 20psi boost...but fit the same unit to a 5.0 and it will be spinning it's head off trying to keep up and be very very inefficient, and probably never make 500hp.

So sizing matters, they need matched to the engine. But it's all about airflow, less about the actual engine. A modern 2.0 4cyl will probably be far more efficient and flow far more air than some old 2v V8 simply through better head design etc.
So comparing a modern 2.0 to your 2.5 per bank isnt unreasonable.

bj928

thanks for the input steve and the other guys, the engines in question are modern multi valve high revving engines, 2015> 5.0 out the new mustang or a Ford GT/GT500 engine from around 2005, already have heads, inlet and a cast iron block for the latter, but may sell and go with the new mustang 5.0, apparently both engines heads flow very well from factory, not sure how they would compare to a modern multi valve 4 pot engine, apparently though, the GT heads are some of the best, but the even newer coyote 5.0 out of the 2015> mustang are said to flow 4% better still


been doing research of what the americans use, and narrowed it down to a Borg Warner Airwerks S300SX3 Turbo-66mm-T4-Open Scroll-0.88 A/R or 0.91 A/R, am i in the right sort of ball park, or would these be to big/small

stevieturbo

A pair of 66mm's like that is around 1400hp worth of turbo.

Probably a little overkill based on what you're asking for lol and you wouldnt have much response below about 4k.

A pair of the 200's I listed to would probably work fine

Look at what some of the Hellion kits are using for the various Fords.

https://www.hellionpowersystems.com/...-turbo-system/

bj928

i would like to be spooling well by about 2500, but these engines rev to like 7000-7500, would a smaller turbo not run out of puff, and restrict the engine, what about variable vane turbos, some used ones of them around, mainly for the diesels in america

bj928

something like this then http://www.ebay.com/itm/Borg-Warner-...5XrwnY&vxp=mtr

stevieturbo

VNT wont be an option. They're difficult to control, and generally not designed to tolerate the heat from a petrol engine.

So they'd just be a difficult choice.

The 57mm S200 SXE would be an option, but bare in mind those are sold as "supercores" with no turbine housing, so you'd need t buy that too, although they arent expensive.

Obviously yes at some point a smaller unit may restrict up top, but if the engine wants to rev it will still rev with the turbo. Will it be as optimal as a larger turbo ? probably not, but then you have to balance spool vs the rest. If you want good boost by 2500rpm, then you will need small units.

The base Hellion kit above seems to use a pair of 55mm Precision turbos, so the small S200's isnt far off.

Even here you could start with the smallest S200 like this, that price is complete

http://www.ebay.co.uk/itm/Borg-Warne...3D262576091330

And if it was lacking in one particular area, upgrade later. But for a fast spooling daily...something like that would do well, and doesnt cost the earth.

bj928

i work in the states more than the UK, so would probably buy in the states just to save a few Ł, i'm guessing i would need a twin scroll manifold making, is a twin scroll better than an open turbo, from what i have read the twin scroll spools a little quicker

stevieturbo

If you have proper twin scroll manifolds then yes it can be better.

Proper twin scroll tubing on a V8 though is next to impossible given firing orders. It just simply becomes tubing to a divided housing, which isnt quite the same thing.

I really wouldnt worry much about it, often short compact manifolds will spool faster than tubular setups which are more aimed towards top end power. Again as per most OEM stuff, some even try and integrate the turbine housing/manifold as a single piece. This too will help retain heat and spool faster as well as make packaging simple ( if a ballix to work on afterwards ! )

And if you do run fully divided tubes to each turbo....dont forget to factor in what that will mean for wastegate requirements. You cant simply vent one side of the scroll

bj928

the engine is going mid mounted in a mk2 transit, sort of supervan style, so space isn't an issue at all, either mount low below the chassis to keep cool, or above in load area on show for all to see, the latter being the better option for going to shows, but i guess the first is best of performance

stevieturbo

If it's for show, then tubular manifolds are probably better, but keep the pipework small if spool is more important. Even 1.75" tubes would be huge.
As for the twin scroll..again, unless routing pipes from one bank to another, it's all but impossible on a V8. So I wouldnt even worry too much about trying to use divided housings. Just pick a good turbo for the job.

Although if the likes of Hellion already make kits or parts, if they sell individual parts it might be just as handy to get some of their stuff

Probably more of a concern for a mid mounted twin turbo V8 that makes any decent power....transmission.

jsa

http://www.turbos.bwauto.com/aftermarket/matchbot.aspx

bj928

thanks for the link, had seen it before, but can't get my head round it, don't know enough

stevieturbo

They are complicated to use, but really not needed. Keep it simple.

And often a calculator to get something just right....can still easily be wrong for your application.

Most OEM turbos are probably a poor choice for top end power, but superb for daily driving. So all round they work great despite the compromises on paper.
They just accept that in many areas it isnt as efficient as it could be, but still perfectly acceptable, but in the areas most drivers would be very fussy about, they work superbly.

Which is much the same here, if you want fast spool, you have to accept there will be compromises at the top, it's just finding the right balance.
But if you want fast spool with no real ultimate power goal, always pick a small turbo. Lag can be one of the most annoying things with a turbo, but even a small turbo can still make great power all the way to redline.
It's a hell of a lot harder to make a bigger turbo spool, no matter how happy it feels up top.

But turbos, especially those BW's are very cheap. It wouldnt be the end of the world to have to change a pair if things turned out horribly wrong. But at least you'd know which way to go after the test.

bj928

i have some time to do more research, i keep looking at the American forums for info, but they are more just into 1/4 mile times, and i'm guessing a turbo that give good performance on the 1/4 may not be much use for daily or track time, they say a 66mm spools fast, and talk of 76mm, but that might work for them, but their idea of fast spool is different to ours, been looking at the S200's as you said they would probably fit the bill, would a modern v8 32v be comparable to say to old cossie engines in V formation, or has technology moved on that i need to look at what the evo guys are using, or does a v8 react differently to 2 4pots

zetaboostboy522bhp

Get the coyote engine and supercharge it , rouse do the kit as do many others , 700 bhp plus no lag just instant power , or you could buy the ecoboost v6 twin turbo and modify that's what guy martin run in his transit van 670 bhp . That will cost a lot more than the coyote engine to tune to similar power levels.

Ag Motorsport build a mk7 fiesta wrc with a mustang coyote engine supercharged and when that came down the straights at donnington that sounded like thunder and went like the clappers. Transmission from the mustang could also be used at they've seen over 1200 bhp from even bigger super chargers on that engine

Even more to think about

Cheers paul

stevieturbo

A lot of American info will be misleading both because they dont know anything other than 1/4 miles, AND most of the cars they will be talking about are automatics, that might never really operate below 3-4000rpm

So when they claim "spool fast", which is another bullshit term with no meaning, it probably means they put their foot down, the car immediately kicks down gears to a much higher rpm and of course it then "spools fast"
But autos can help apply load to the engine too which can assist spool even if it did manage to stay in a particular gear so can spool a little better than doing the same in a manual.

Again it's all about airflow. If your 2 x 16v 2.5 engines flow similar air ( ie the V8 ), operate in similar rpm's to a regular 4cyl 16v 2.5 engine, then yes of course they can be compared.

Given you want spool and not total power, if you aimed for what works well on a 2.0 16v engine, then just buy 2 of those and you can be sure they'l spool faster on your engine, albeit at the slight expense of losing a little up top.

There are many VW 2.0 turbo petrol cars, Mitsi, Subaru, Saab/Vaux, Volvo, but some of those turbos will be odd fitments. But all modern stuff use really tiny turbos these days and they still produce great power compared to the shitty old T3 for example a Cossie used.

stevieturbo

Of course, the supercharger is the ultimate option for your instant low rpm power, and given they're fitted to so many of the 32v Fords, should also be a very cheap and easy option.

Or just buy a Mustang Cobra complete setup. Job done.

bj928

the coyote is the 5.0 choice, and i am hoping to get a crashed salvage mustang later this year as a donor to the mock up i'm doing on a mk6 transit, the mock up will be engine, flappy paddle auto (2015> factory fitted) and irs back end, using the shortest prop shaft i can get away with, the engine shouldn't sit to far forward, but may have to sit under the seats just very slightly, i would have preferred a transaxle but the costs are to high on top of everything else, the coyote for now will just be standard with maybe a cobra jet inlet (because i like the look of them) and maybe a tune, as said, this is a mock up, to see if everything works as a mid engine setup, and by running everything standardish it will still be quick and have getting on for 500hp at the flywheel, but it will be reliable and to a degree plug and play, i have the heads and inlet from a 2005 GT supercar, and a 5.4 cast iron block for them to go on, this is the engine i want to turbo, but if i find the coyote is a nice engine to work with i may well sell the heads and inlet and go with the coyote,

bj928

the supercharger option is good, but i would want to intercool it properly, not use the water to air system they use normally, the water to air works for the Americans because they only to 1/4 mile then it can cool down, for track time i see it having to much heat soak, being that its going mid engine in a transit and height isn't a problem, an adaptor plate could be fabricated to channel the superchargers air out to and intercooler then back into the engine

bj928

my friend want me to go the turbo route so if we want more and more power its just a case of fitting bigger turbos, the 5.4 bottom end will be as strong as is possible, way way more than i will ever need, but i want to do it once and once only, the rotating assembly will be from MMR, and it will be the best they do

stevieturbo

Water cooler can be effective if done right, or add one of the interchiller things they use now, that use the aircon to cool it.

To try and add a remote air to air intercooler to such a blower install, would be very difficult and often not worth the effort. Especially as you're saying it isnt a big power build.

I'm sure the factory parts and cooler would be quite adequate, and also not difficult to improve upon

bj928

what would you class as big power, what power are you running, the engine i'm starting with will be good for 500hp without any form of blower, either turbo or supercharger, will be 32v and have very good airflow, i know they get some silly amounts of power out of both engines, would 1000hp be realistic without to much lag, or should i aim more for say 800, 1000 is just a nice round number to be aiming for, if i have to come up with a power to aim for, the Americans seem to get way over this but with big laggy turbos for 1/4 mile,

you said earlier about the auto making a difference, at the time i am planning on using the Auto with flappy paddle out of the 2015> mustang, and the flappy paddle comes factory, and saves me trying to get a gear linkage to work half way down the back of the van, a lot easier to run some wires, and also i think flappy paddle would be quick trick, not sure if i will like it, so the turbo build might get some form of manual, i like to be in control of my own gear change, but a lot of modern cars seem to be going flappy paddle

stevieturbo

I'd say the modern auto with paddles to shift will work very well, and as it's also going to shift down etc very quickly, lag will be less of a concern.
Would the factory car even let you use say 50-100% throttle at 2500rpm in any gear ? or would it always kick you down to a higher gear ?
So how important really is good spool/boost by 2500rpm be ?

What control do you have over the box's shifting ?

And what layout is the box in a Mustang, that it can be used as a transaxle as you propose ?

But if you want 1000hp from a base engine of 500hp, then of course there is going to be some lag.

Again though, a pair of the BW's etc are very cheap. Just build the kit now and one way or the other if you do need to change them later, it's dead easy to do so and wont cost a fortune. And old units are always sell-able somewhere.

bj928

it won't be a true transaxle, but will be a very short engine/gearbox with tiny prop to the mustang irs, the 6r80 auto in the mustang is very short compared to older gearboxes, and the coyote is only 26" long and the 6r80 is only 27" long from bellhousing to engine face, so 53" long, not very long at all, from the centre of the wheel the snout of the diff comes 10" forward to join prop, so have the shortest prop made i can have, and it should work out nice and cheaper than a full on transaxle, although i will be looking into a hybrid of the corvette transaxle to mount onto the 5.4 with a tr6060 or t56

don't know how much control the cars ecu give you over the shifting on the paddles, don't know if you get 100% manual control,

i didn't realise there would be a difference between setting things up for manual or auto, but now you have said about it it would make sense, and if i get on well with the 6r80 i may well go for a built one in the final build, the 6r80 is a 6 speed flappy paddle/auto, seems to be a nice box,

stevieturbo

I'm sure there are people out there who've hacked the gearbox controls one way or another to let you do what you want.

But standard....they'll almost always kick down when you nail the throttle, so any concerns about low rpm use or torque...arent really a concern at all.

A bit like years ago I bought a 525tds where BMW claimed the engine made it's maximum torque from as low as 1900rpm.

That's nice...except in my auto 525tds, it was all but impossible to have the engine at 1900rpm...or even 2500rpm !! It was one rev happy piece of shit.
Barely touch the throttle and it was immediately down gears.

Autos arent really my cup of tea either, but there is a simple reality that for straight line stuff at least they do launch better, and put the power down better...and there is no letup in acceleration until you let off because all shifts are foot to the floor.
And with the modern stuff, the driving is nothing like slush boxes of old.

I'm not quite convinced to swap yet...but someday I could be. And through all of it, you retain quiet smooth driving.
And even for ore sporty driving the fact it's a flappy paddle...again, cant be bad at all.

bj928

the flappy paddle makes fitting it behind the driver a hell of a lot easier and cheaper, and by the sounds of thinks, i could maybe go for a slightly larger turbo than if i was going manual, if i was going normal front engine rear drive i would go manual in a heart beat, i haven't a clue what these new modern autos are like, but most race cars are now flappy paddle so can't all be bad, the mock up mk6 won't be turbo'd, well not at the moment, but never say never, the mk2 is about 500kg lighter, and so will be real nice when turbo'd, i got the mk2 transit a month or so ago, thats going to get a lot of mods before it even sees an engine, and i will have to decide if i'm going 5.0 or 5.4, guessing the 5.4 will give more torque than the 5.0, and the 5.0 will be revvier,

will higher compression help spooling, i want to run 9.5:1, but would 10:1 be an option with a modern build

stevieturbo

Unless you have decent fuel, I wouldnt be keeping the high CR. Again the yanks now love that, but they have E85 everywhere. We dont.

I would not be going over 9.5, and erring on the very safe side I'd probably go for 9.0:1

For minimal loss, it will just widen any tuning window and mean if you want more later, there is little risk running much higher boost.

As for torque, yes a bigger engine will always produce more torque. And as for rpm's, very much camshaft dependent.

I'm sure a modern auto isnt as good as a DCT flappy paddle...but I'd still say they would be very very good and as you say many many top end cars are still conventional autos with lots of gears and there are few complaints about them

bj928

what engine and turbos are you running to get a 9.85@145, and what sort of power,

stevieturbo

That time was my LS and a Vortech Supercharger 9 years ago. No idea on power....clearly not enough