hoffdaddy

I'm not worried about oil being sucked out of the bearings when the throttle body is closed. How well will a draw through turbo work with the same fuel injection system that the car comes with from the factory. I don't see how it wouldn't work. I'm just trying to figure it out. Also can a fuel injected draw through have a water to air intercooler? No fuel passes through it, I don't see a problem. Maybe no not.

4drEF

What engine are you talking about here?

I don't think I have ever heard of a draw through on a modern fuel injected system.
Since modern fuel injection mounts the injectors in the intake manifold, there is no way to draw though.

Old carburetor and injector mounted throttle bodies could do it.
You mount the carburetor before the turbo, the turbo pulls in the air/fuel mix from the carb (draw through), and off to the intake manifold goes the pressurized air/fuel mix.

You don't get an intercooler with draw through.
The fuel is cooling the charge so you really don't need one.
You can add a water/meth injector after the turbo if your charge needs to be cooled more.

If you did add one, the atomized fuel would form droplets all over in the intercooler and you would have a lake of fuel in the intercooler very quickly.

hoffdaddy

Any Honda engine really, probably like an h22. Sorry I guess draw through with fuel injection isn't really draw through, but it still draws through the throttle body only difference is there's no fuel like a carburetor. I just want to know if it will work, I look all over the Internet and I only see the idea get bashed on.

NotARaCist

iTrader: (1)

So you want to mount your throttle body on the turbo inlet, rather than on the intake manifold? That would absolutely send your throttle response to ****. Also, your turbo would be spinning regardless, which would kill the vacuum your engine needs to idle. Even if you could deal with the lack of vacuum, your throttle response would be garbage, and if you intercooled it, it would be even worse.

4drEF

I see absolutely no reasoning to do this - but - what if you used one of those top mount manifolds that locates the turbo over in front of the distributor.
If you went NO intercooler, would throttle response still be terrible?
Would you even need a BOV for this?

NotARaCist

iTrader: (1)

Since the throttle plate won't be there to create pressure outside of the engine, I don't think a BOV would even do anything. As for throttle response, the more piping you add between the throttle body and the plenum, the worse your throttle response will be. If you fabbed something up to move your turbo right near the TB to minimize that, then you would have so much piping in your manifold, your turbo response would go to ****. It's a catch-22 - You either have one problem, or you have the other. I can't think of a way to solve both, short of having a head that works like VW diesel heads, which have the intake and exhaust ports on the same side of the head.

DC_Legacy

I haven't seen a draw-threw system since I was a kid from a handbook on turbo charging out of the 80's......and these were carbureted chevy SB's mostly......

hoffdaddy

Here's what I want, but a water to air intercooler instead.

There is a ton of piping after the turbos! There is no way that a F1 engine like this had bad throttle response. Another engine that had this was the BMW M12/13, a 4cyl, and the most powerful F1 engine ever made.
I'm not making an F1 engine, I'm merely testing the concept on a Honda. Now my mind is blown, how do they not suffer bad throttle response? Is it because of forced induction, because you can't move the tb that far away on a NA?
I've done more research and only found out that anything before the turbo is a bigger restriction than after, on carb draw throughs they had enormous carbs feeding them to negate the restriction. A very large butterfly throttle body is a lot less of a restriction as a carburetor.

NotARaCist

iTrader: (1)

Trying to compare an F1 engine to a Honda 4 pot is...well, you're comparing apples to elephants. They're both round, but the similarities end there.

Then again, I could be wrong. The turbo could be keeping air "stacked up" in the plenum, negating the throttle response issue. Then you still have pressurized air constantly beating on your valves, and no vacuum. I just don't see it ending well.

met

Hell, give it a try and let us know how it goes. Looks really neat haha

hoffdaddy

There is no pressurized air the entire plenum including the turbo is a vacuum with the throttle shut. Maybe its because the impeller doesn't slow down unless you let it slow down, it doesn't have any resistance to stop it in a vacuum. So, from idle the plenum is not a vacuum, open the throttle and the boost comes on, no bad throttle response. Also if you shift at say 6000rpm, turbo is making 16psi boost, shut the throttle, shift, engine at 4500rpm, turbo makes 15-17psi when you come back on the gas, no lag, no bad throttle response.
Yes, I do have to try this some day, but point it out if I'm wrong here.

m4xwellmurd3r

F1 cars still had traditional throttles at the head. They used the pre turbo throttle plate to manage turbo lag. By closing the plate when it goes off throttle it causes the turbine to spin up as it enters vacuum. Then when they get back on the gas the plate opens and the turbo is still fully spooled, resulting in no lag.

If you only had the throttle pre turbine you wouldnt have turbo lag, you would have throttle lag because the intake tract is so long

Dallasb84

You can't compress air in a vacuum. However. A "blow thru" system pictured above has near instant boost.

The turbo will stay spinning even when the throttle body closes.... But. No cool laser beam bov sound is what I gather. Interesting setup..... It would be neat to understand it more.

hoffdaddy

I had wondered if they still had itbs, in my picture it didn't look like there were any throttle bodies near the intake manifold, but knowing f1 they're probably in the head or something. As long as I don't need a bov it doesn't kill the purpose, I can still try it.

F22Master

Those engines DID have horrible throttle responce... and a powerband thonner than a human hair... anything below ~9k and they were slow as dog ****, then once they hit boost (~4 bar I think, 60psi) they spun the tires until you let off, or shifted. Then rinse and repeat for the next gear... thats why only a few people were really fast in those cars. It took the absolute best of the best to.keep them in the powerband, but without melting the tires instantly lol

I wouldnt want to copy much of anything from an engine with characteristics like that...

F22Master

'The M12's major shortcoming as a Formula One engine was its lack of throttle response, sometimes called turbo lag. Unlike the V6 and V8 turbocharged engines which ran with twin turbos (one for each bank of cylinders), the inline-4 BMW engine, like the other 4 cylinder turbo engines used in F1 such as the Hart 415T and the Zakspeed 1500/4, only used a single turbocharger. The twin turbo setups of the "V" engines eliminated much of the turbo lag. However, with only a single turbo, the BMW M12 suffered from approximately 2 seconds of turbo lag meaning drivers often had to start accelerating through the apex of a corner. The power from the turbo was described by many (including Piquet and Berger) as coming on like a light switch which often induced power oversteer in BMW powered cars. This was a major reason that the BMW was generally seen at its most competitive at power circuits such as Kyalami, Imola, Paul Ricard, Silverstone, Hockenheim, the Österreichring and Monza. On tighter tracks such as street circuits like Monaco which required greater acceleration and less top speed, the BMW powered cars often lagged behind their major rivals.'

hoffdaddy

Oh ok then... I just watched some videos of the guys revving the engines and it seemed pretty responsive to me, but I might just be crazy. I did know a lot of the cars didn't have wastegates, that might be part of the narrow power band problem.
Edit: look at the size of the turbo on the m12/13, no wonder it took so long to spool it's at least the same size as the v8 and v6 engines. They made 60psi from their turbos (aand that was limited with the FIAs pop off valve) I want 8-12psi that's plenty, I can cut down on turbo size a lot. Impeller quality is a pretty big deal though.

m4xwellmurd3r

Thats horrible turbo response. Throttle response is different. Because of the turbo size and boost needed, they lagged for days. Without the boost the engines had zero power, once the boost came in it was like being hit by a freight train.

If you look up some examples of f1 cars utilizing pre turbine throttle plates youll see they still had throttles at the head too.


Heres a good picture that shows both the pre turbine throttle, the cable going to the main itb linkage, and that it retains itbs



Btw the image is of a bmw m12/13 1.5L 4cylinder. As you can see the turbo is nearly as big as the whole engine! So utilizing the pre turbine throttle plate was needed since that tiny *** engine needed to spool that huge *** turbo.

http://www.gurneyflap.com/bmwturbof1engine.html

hoffdaddy

So does anyone know if the preturbo throttle plate opens/closes the same time as the itbs or is one delayed. I would think they'd simply open/close simultaneously.

m4xwellmurd3r

From what ive seen they open/close at the same time, but I dont know if they open at the same rate.

Most likely they opened at the same rate, as I cant think of any advantage of the preturbine plate opening faster/slower than the main throttles.

I found this interesting design renault used

https://farm8.staticflickr.com/7177/...8cd305fd_b.jpg

It appears that intake air only entered around the rim (the mechanism has a cover) and they adjusted multiple vanes to close the intake pre turbine. It looks restrictive but the turbine inlet is actually pretty small

hoffdaddy

Interesting. I would love to see renaults little thing in action.

Dallasb84

Man I was way off in my assumption! Pretty cool info. How much power did these things do?

hoffdaddy

Way more than they put out today! The bmw m12/13 was the highest outputting, it made over 1000hp at about 2bar, every .1 bar after that was considered 20hp up to 4bar. It was guessed 1200-1400hp. I see other engines produce from 650-750hp to closer to the m12/13, and they some were i4, v6, and v8.