Q45 Rear Mounted Turbo

[dareo]

So my friend is turbocharging his MB 190E with a rear mouned setup. basically welding in a turbo near the muffler and piping it to the intake with a seperate oil resevoir.

Is there room for something like this on a Q45? I've only owned mine for maybe a month now and haven't spent enough quality time under it.

Theres even a company here in Utah, i believe STS turbos, that fabs up a rear turbo system for a lot of cars, but they want lots of $$$ so we're doing his benz on our own.

[911/Q45]

Seems like the turbo lag on a setup like that would be measured in hours!

[HeavyDuty]

I agree, heat is what drives the turbine. Imagine the loss of temp between the manifold & the rear tires.

Needless to mention the plumbing from the back of the car to the front, and mounting the MAF under the car in an oh-so-clean environment.

Watch out for that puddle!

No thanks.

[psychic_mechanic]

Those "systems" are crap. I've seen the turbo mounted directly under the gas tank as well.

[sijoko]

Don't rule out a rear mounted turbo kit.

There are some fast cars using the same setup.

It is a compromise, but it can be made to work.

I consider it more of a last choice turbo setup.

The only benefit is that you will not be messing with any of the emissions controls, so there should be no problems with passing the emissions testing.

-sijoko

[PoorManQ45]

Hey look, Somebody made a new thread about something that I already talked about. But you didn't just say it wouldn't work, you said why it wouldn't work.

Ok, a rear mount turbo will work. To reduce lag, you would go with two smaller turbos. This would allow them to spool up faster than larger ones.

Um. A turbo is not turned by the heat of the exhaust. They a turned by the pressure that they induce into the exhaust system.

You do not need to put the MAF underneath the car. That would be dumb. You would put it near the Throttle Body.

A remote mount turbo can and will work. Plumbing it in is a problem though.

[1qckser]

[QUOTE=You do not need to put the MAF underneath the car. That would be dumb. You would put it near the Throttle Body. [/QUOTE]

OHH yes you do need to put it under the vehicle, seeing how the turbo is mounted underneath the vehicle, and you have plumbing running back up front to the TB the MAF has to be inline in front of the turbo to meter the incoming air, and not to mention on a MAF system the blow off valve has to be recurculated back into the system after the MAF or the car will run like crap and will stall on deceleration, this system is much more suited for a map system than a MAF setup.

http://www.clublexus.com/forum...ber=1

[HeavyDuty]

I've seen videos of these kits in action. I never said it wouldn't work, but it is the least desireable option on the planet, IMHO, of course.

Um. A turbo is not turned by the heat of the exhaust.

Hmmmm, why don't you call and waste the time of an engineer at Garrett & have them explain it to you. Even you can understand hot exhaust gas "flow" yields more than cool. You wouldn't know a turbine if it sat on your face & wiggled.

They a turned by the pressure that they induce into the exhaust system.

WTF are you talking about now?

You do not need to put the MAF underneath the car. That would be dumb. You would put it near the Throttle Body.

Dumb, huh?

Am I the only one who hears Calliope music in the background on these posts?

If it's a rear mounted turbo on a MAF equipped car and it does not utilize a blow through MAF, it sure as hell does need to be mounted before the turbo. Blow through MAF's work GREAT on street cars, you should try that.

A remote mount turbo can and will work. Plumbing it in is a problem though.

Then stop wiggling your fingers about it & do something, do anything, but for chrissakes, stop being a PITA on subjects where it's painfully obvious you haven't a fvcking clue & further exemplify your ignorance with belligerance!

I am not an expert. Someone like Tech could bewilder me with data on this or any other subject. However, the difference between me you you, PMQ, is that I've actually done the things that I speak about in this forum. If I don't know, I say I don't know. I don't try to BS those with more experience than I nor do I badger them with uneducated retorts.

[PoorManQ45]

Hmmmm, why don't you call and waste the time of an engineer at Garrett & have them explain it to you. Even you can understand hot exhaust gas "flow" yields more than cool.

This it how I interpreted what you said about the turbo be spooled. "Only the heat from the exhaust causes the turbine to spin. There does not need to be any pressure in the exhaust." Is that what you meant?

So... a turbine is somehow turned by the heat of the exhaust? Just the heat?

You're saying that there is no pressure in the exhaust, before a turbo?

The pressure generated by the exhaust stroke forcing exhaust gases out of the combustion chamber is what turns the turbine.

[s13sr20chris]

This it how I interpreted what you said about the turbo be spooled. "Only the heat from the exhaust causes the turbine to spin. There does not need to be any pressure in the exhaust." Is that what you meant?

So... a turbine is somehow turned by the heat of the exhaust? Just the heat?

You're saying that there is no pressure in the exhaust, before a turbo?

The pressure generated by the exhaust stroke forcing exhaust gases out of the combustion chamber is what turns the turbine.

ideal gas lawPV=nRT

if temp goes up then pressure goes up. also note that heat is on form of energy and that energy does not just dissapear(conservation of energy or something like that).

[HeavyDuty]

So... a turbine is somehow turned by the heat of the exhaust? Just the heat?

The pressure generated by the exhaust stroke forcing exhaust gases out of the combustion chamber is what turns the turbine.

No, and not exactly.

Not just the heat, but primarily the heat or use of the hot expanding gases, waste energy.

If your engine were an air pump only (no fuel/spark) the exhaust stroke by itself would not generate enough "air flow". The operative words in your second sentence above is "exhaust gases".

I found a short article that does a good job of explaining it. I know the concept doesn't make sense at first, but this is written so you don't have to be an M.E. to understand it. (Perfect for a Dumb Country Boy like me)

http://www.turboclub.com/turbotech/TurboFun2.htm

IMHO, my point of the rear turbo being less efficient than a conventional is that the gases have cooled significantly by the time they reach the turbine at the rear of the car. I can only postulate that a correct fit turbo for the application would take a lot longer to spool up. (Create boost) The only positive side I see is that if the turbine is cooler as a result, perhaps the charge air from the compressor side would be cooler too. But when you compress it, it heats up anyway.

Then you have the issue of oil feed/drain, and charge piping under the car, etc.

I've seen, driven, installed, and built many different types of power adder systems on different cars. I am opinionated, but only because I've seen people make bad decisions they regret based on only the good side of a story or pitch. Make sense?

[PoorManQ45]

Ok, thank you very much for clearing that up for me. Also, thank you for not jumping all over me again.

[s13sr20chris]

we are not a "jumping" bunch. tell you what. go post your questions at http://www.eng-tips.com and see what happens. those guys will be on you like rabid dogs. we are really quite nice.

[HeavyDuty]

This is a good group of guys, PMQ. I don't want this site to turn into the one sr13sr20chris mentioned.

You can catch more flies with honey than vinegar.

Go search any previous post in the last year dealing with any of the subjects you've mentioned & you'll see virtually no argumentative posts.

Well, maybe except for Wes & Ryan.

[AZhitman]

Well done, HD.

For those of you who don't know, HD is quite the accomplished tuner. Probably works on more haul-arse Honda/Acura cars than you can imagine, and is pretty handy with the FWD SR and B15 as well...

[1qckser]

Well done, HD.

For those of you who don't know, HD is quite the accomplished tuner. Probably works on more haul-arse Honda/Acura cars than you can imagine, and is pretty handy with the FWD SR and B15 as well...

Well done, HD.

For those of you who don't know, HD is quite the accomplished tuner. Probably works on more haul-arse Honda/Acura cars than you can imagine, and is pretty handy with the FWD SR and B15 as well...

Yeah,and if you are ever in Broward County and get stopped by a COP driving a new GTO with a NOS sticker on the back window you can thank Heavy for the ticket

[HeavyDuty]

Thanks AZ, there are many here far more formally educated than I. I'm just here to glean information from them about my personal car.

I only know from asking & doing. Only a couple of peole here even know I've owned a shop for the last seven years.

[dareo]

I'll let my friend know to insulate/heatshield his exhaust to preserve as much heat energy as possible as the exhaust passes back to the turbo. Hopefully his setup will yield some good performance. If it turns out crappy we'll probably put a 1JZ or RB20DET in the 190E.

[MiniMan]

I agree with what you said HD. Many questions must be asked and/or done. However, there is always research which should be done before asking. Whether that be searching the archives (which is why they're available) or searching google. I see 95% of the newer members out there do it and it's always nice to see that number raised. Don't think that I'm looking at just you PoorManQ45... There's a reason why Maxnix has that search button in his sig.

Corey