Double turbo blower v8

[jalopi]

Sup bros, wondering if anyone could help me out with a crazy idea I came up with the other day.

Key point one: ever seen a jet engine made out of an automotive turbo? It's pretty cool



Except for that most uses the only thing they're good for is making alot of noise and putting out a shit ton of exhaust. Which got me thinking... what if you powered a TURBO with one of these things?

(artists' rendition)


Why would you do this, you ask? In theory (well in my head anyway) the turbo engine would spool up the other turbo so that it'd be running at full boost... always. Your power/torque curve would be RIDICULOUS from idle to redline and the best part is the power would be pretty much linear.

So why don't more people do this? Aside from the added complexity, after running some figures it seems that setup would burn a TON of fuel. Lets say I decided to use a t25 for the jet engine. How much fuel would that burn? Well lets take a look at the compressor map



Depending on the operating pressure, I'd be moving roughly 10-16lbs of air per minute while keeping the compressor within its best efficiency range. With gasoline, at a stoich of 14.7 you're looking at a fuel consumption rate of about .68~1.088 lbs of gasoline per minute, which roughly translates to 6.5~10.3 gallons burned per hour. Ouch. Size up to a t3/t4 and you basically double the consumption.... double ouch.

Now obviously with something like this you'd want to keep the fuel consumption as low as possible, for economical reasons, which is why I'm here: does anyone know how to calculate how much exhaust flow a turbo needs to spool up? There are calculators online where you can put your engine size & other stuff in, but they don't really give out their estimated flow rates

Basically I'm toying with the idea of putting one of these in the trunk of my e36 since engine bay space is really limited and this would allow me to drive it like a normal car (two tunes, one with the turbine setup off, one on) yet kill it during track days with a zero lag turbo car that sounds like a fighter jet :)

Not only that but I'll be able to use the same system with very little modification when I do my v8 swap again, hence the trolltastic thread title.

Thoughts on this?

[Nesset]

My thoughts... Use the pencil tool on MS Paint next time you smoke crack.

Actually rather interesting..

[whodwho]

For one you would have to throttle it so it had a linearish output to match engine RPM/load then you would have to be able to shut it down instantly and have some serious blowoff valve when you lifted.

Not to mention those things are finicky as fuck and slow and a bitch to light off

[pandaboo911]

Or you could just use the pre-existing, easy to install, reliable solution called anti-lag.

Have fun burning your car to the ground lol

[jalopi]

torching my car is really the only legitimate concern i have, lol

as far as why i don't wanna do antilag... well there's a few reasons.

for one, i plan on remote mounting the turbo - the e36 engine bay is cramped as-is with a v8 swap, i'm not trying to make things even more cramped and add extra heat under the hood if i can avoid it. the point i'm getting at is that i'm not sure how effective antilag would be with the turbo being so far away from the engine.

also, while antilag sounds pretty sweet, jet noises are even better :D

[jalopi]

Btw this is the source of my inspiration:

http://raceenginedesign.biz/Manic-Beattie.htm

quoted incase you guys don't feel like browsing through the whole article:

“With 400 bhp the initial aim, it was evident that a move to a larger turbocharger and quite a large amount of boost would be necessary,” says Mann. “This would result in the dreaded turbocharger lag and while anti-lag or ‘bang-bang’ systems were considered, it was quickly decided to move to a much more radical solution.” Mann’s background in aerospace led him to a solution involving a helicopter gas turbine APU or auxiliary power unit. Supplied by Turbine Technologies Ltd of Carmarthenshire in South Wales, the unit is based on a helicopter emergency air start unit used to fire the main gas turbine engine on the ground.

Running separately from the main engine, initially on diesel fuel, the unit delivers air to the engine at a constant pressure independent of the main engine speed and hence totally eliminates the throttle lag normally associated with high boost turbocharged systems. Currently set at a very “modest” 25 psi gauge boost, the engine delivers something in the region of the initial target of 400 bhp at 7500 rpm. The torque curve is particularly impressive: from 2500-7500 rpm this doesn’t vary by more than 20% from the peak value.

[IronFreak]

Well......I'm intrigued now.....

[cgk_iii]

My thoughts... Use the pencil tool on MS Paint next time you smoke crack

[Brezzi]

Do it you won't!

[jalopi]

lol but seriously i'm trying to figure out how small of a turbo i can use for this setup, anybody have thoughts on a t25 spooling up a hx35 or a t3/t4 or something? using pretty much anything other than a t25 will double my fuel consumption

[mrcheezle19]

I saw shitty hand drawings and figured troll. Then I read it and

[TheTacoMan]

Compound turbo setup would work similarly.

[jalopi]

considering maxing out the exhaust flow wouldn't be an issue, could a t25 be used for the engine and replace the t25 compressor housing/wheel with something much larger?

*** edit

after doing some reading on t3's, it looks like i can get something with roughly the same turbine housing/wheel size as a t25 but with a much larger compressor. not sure if it'll be enough... but we'll see

[goarmy]

[mrsleeve]

Why not just put a blower on it and stop over complicating the problem . It gives you the space savings you need and NO LAG........ Plus the parsitc drag you lose is not going to be enough to worry about your building a street car not a all out ever last oz of performance engine here