trogdor
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| posted on 1/6/08 at 01:04 PM |
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Turbo mounted in place of silencer
Hey all,
Has anyone else read the most recent copy of PPC? it has a pug 205 with a turbo mounted with where the silencer in the exhaust would be!
sounds abit crazy but there were good reasons, such as better weight distribution, no intercooler needed as there is no heat soak from the turbo and
if the intake piping runs under the car it is cooled here too. This means a standard 1.9 GTI engine could be boosted with only uprated injectors and
mapable ECU needed. The oil needed for the turbo was provided by a scavenger pump.
The most obvious disadvantage is turbo lag, which appartly is no worse than anyother comparable turbocharged car.
Theory is that a standard small bore ehaust keeps the back pressure up so when you hit the throttle the turbo will respond quickly due to the back
pressure. The lag only coming from the intake piping which if it runs under the car direct to the throttle body means its not much longer than if it
had to go through an intercooler like in a more normal situation.
If the lag is not too bad it sounds like a great idea, as its also cheaper to install.
What do people think?
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blakep82
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| posted on 1/6/08 at 01:07 PM |
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i think you lose some pressure in the intake pipe too, but its been done many times before, somewhere on youtube it an american car (mustand i think)
with that set up. seemes to work ok for them
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ravingfool
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| posted on 1/6/08 at 01:09 PM |
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an interesting idea, but I presume it would be of no use to anyone already running a larger bore performance exhaust which will run at a lower
pressure?
ETA: And what about speed humps?! everyone expects to hit their silencer on humps from time to time and this tends to cause little damage because of
the flexible mountings and exhausts are not sensitive pieces of equipment. Surely though whacking your exhaust on a speed hump is going to ruin your
day?
[Edited on 1/6/08 by ravingfool]
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trogdor
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| posted on 1/6/08 at 01:28 PM |
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apparently it was mounted on a exhaust hanger in a similar way to an exhaust silencer. so i guess it would have the same sort of movement like a
normal exhaust but that said wouldn't want to scrape it!
The car was a sprint car so i guess its not too much of a problem.
If i did it, i would mount it to provide protection and maybe have a shield on it.
If u had a big bore exhuast then it would be no good, you would deffo need the lower bore exhaust.
[Edited on 1/6/08 by trogdor]
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MikeRJ
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| posted on 1/6/08 at 01:29 PM |
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It's never going to be as good as a turbo mounted in the proper location. The exhaust gasses cool and lose quite a bit of energy before they
get to the tailpipe, this is why you need to keep a pea shooter exhaust on it to keep gas speed up.
The you have the hassle of routing the induction pipes and oil lines, plus a scavenge pump for the oil return since the turbo will almost certainly be
mounted around sump level.
The only advantage I can see is the turbo will be running much cooler, not putting as much stress on the oil etc.
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Benzine
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| posted on 1/6/08 at 03:00 PM |
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I'm putting two turbos on my engine, guess I could branch the two post-turbo exhausts into one and then put another turbo on there... ^___^
tri-turbo ^__^
[Edited on 1/6/08 by Benzine]
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trogdor
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| posted on 1/6/08 at 03:05 PM |
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Am thinking it might be a good idea for a mid engined car, as it could be mounted far enough away to aid cooling, but close enough to reduce turbo lag
enough so its not as bad as a front engined car.
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britishtrident
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| posted on 1/6/08 at 05:36 PM |
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Apart from anything else Turbo lag will increase greatly.
Personally I'll stick to proven rock solid power boosting gizmos like one of those little electric fans ya can buy put in the airfilter intake
and if that dosen't give enough power I'll connect a very expensive ressistor you can buy off ebay to the Coolant temperature sensor.
--- Do you think I should fit a magnetic fuel catalyst as well and may be a supper dooper spark booster for the ht leads.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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blakep82
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| posted on 1/6/08 at 05:41 PM |
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quote:
Originally posted by britishtrident
Apart from anything else Turbo lag will increase greatly.
Personally I'll stick to proven rock solid power boosting gizmos like one of those little electric fans ya can buy put in the airfilter intake
and if that dosen't give enough power I'll connect a very expensive ressistor you can buy off ebay to the Coolant temperature sensor.
--- Do you think I should fit a magnetic fuel catalyst as well and may be a supper dooper spark booster for the ht leads.
well, it works for these dudes...
more here - http://www.chevyhiperformance.com/techarticles/148_0502_rear_mounted_turbo/index.html
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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Mr Whippy
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| posted on 1/6/08 at 06:11 PM |
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weird, it could take ages for all that pipework to build up pressure.
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will121
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| posted on 1/6/08 at 06:12 PM |
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it looked a simple cheap way to more power, may not tick all the normal boxes but ive now got the urge to try it on my track day zetec Fiesta, was
looking of going the Grifin inlet manifold roure first, which would seem easy to upgrade later with the rear turbo.
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blakep82
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| posted on 1/6/08 at 06:21 PM |
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quote:
Originally posted by Mr Whippy
weird, it could take ages for all that pipework to build up pressure.
yeah, true enough, it perhaps won't give the maximum power possible, but would still give some boost. as with everything, its a compromise i
think.
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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JoelP
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| posted on 1/6/08 at 08:02 PM |
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if you insulate the exhaust then it wont cool as much before it reaches the turbines, hence more pressure to use.
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Ivan
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| posted on 1/6/08 at 08:12 PM |
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I'm with those who think it is a seriously bad compromise for all sorts of reasons. The principal one being loss of exhaust gas volume/pressure
due to cooling - a couple of feet from the head the gas would be approximately half the temperature i.e almost half the volume and pressure. It might
not mattrer too much with a very small - low boost turbo but will deffinitely impact seriously on lag.
This might however work on a large displacement motor as per a V8 like the example above where the turbo is significantly smaller than twins normally
used and only produces around 7psi boost.
I don't have my calcs around but a temp of 175F for 5 psi boost sounds high so I would guess that the turbo is fairly inefficient - but maybe
I'm wrong.
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