blundar

Curiousity: What kind of EXHAUST MANIFOLD PRESSURES are people running with a Full-Race equal length tubular manifold, T3/T04 turbo lets say .63AR for sake of argument. 1.8L B series motor, idle-8500 RPM range.

Pressures in vaccum while cruising?
Pressures at WOT spooling turbo?
Pressures at WOT/Full boost with wastegate open?

Thanks in advance,
-Dave

DIRep972

iTrader: (1)

ummm, im just interested who is actually able to datalog this information on this website ahahaha....

i know of a few that can but they are not right now.

blundar

I figure someone will have the information... Maybe.

st00pid

Tony1 is the only person I know that has datalogged backpressure, but Im certain it was on a turbo slightly larger than a T3/T4.

blundar

I guess I'll try to get ahold of him...

DIRep972

iTrader: (1)

yeh, the turbo was just a little bit bigger then a t3/t4 and the car was on meth hehe. but it might help ya. btw, what exactly are ya trying to figure out by knowing the back pressure?

blundar

how much boost it will take to have a favorable intake / exhuast manifold pressure ratio

Ekasey

We have the means to measure it and the tools if you provide the engine etc.

Full-Race Geoff

weve only tested it on two race cars so far, and one was a .96 ratio, the other was about .97. very similar setups

DIRep972

iTrader: (1)

Cool, well hopefully your idea w/ the wastegates will work and help out w/ the exhaust back pressure.

Are you going to be able to datalog this on your set up? I think its going to be hard finding this info for a t3/t4 turbo. You might just end up having to do the testing yourself if you don't wanna just go w/ the "what already works" path.

blundar

Casey: I'm not local to you. Shipping you a motor, turbo manifold, turbo for testing would be prohibitively expensive. 8.5:1 Compression stock bore B18B honda motor, Full Race Manifold

Geoff: I'm interested in the exhaust backpressure at different conditions, particularly the wastegate-open full boost condition. How much boost were you running to get these .96/.97 Intake manifold/exhaust maniflold ratios? Without knowing how much boost you were running, that's not helpful information.

blundar

DIRep: I'll probably end up testing this myself, yes. I'm trying to get some idea of how much backpressure a T3/T4ish turbo generates once fully spooled and the majority of exhaust is bieng dumped out of a wastegate. I know this will vary with my particular setup. I'm just trying to get a ballpark figure so I have some better guidelines for engineering the rest of the motor. (i.e. piston compression ratio)

There are very good things to be had with an intake manifold / exhaust manifold pressure ratio greater than 1.0, as I'm sure some already know...

Full-Race Geoff

when i say .96/.97 i am reffering to this being equivalent to 45 psi intake, 43 psi exh and so forth.

I think we should agree to set one nomenclature straight, whether it is exh/int or int/exh. I have always seen exh/int. ideal is below 1.0 for no reversion

The ratios vary according to shaft speed of curse, but this was an average taken on a car with a very large turbo and anywhere from 32 psi to 48 psi

blundar

Intake
--------
exhaust

This ratio will be > 1 when there is more boost than backpressure. This ratio will be less than one when there is less boost than backpressure.

Do you+I have our numerator/denominators switched?

The data that you are describing is interesting, although everything I've turned up in my research suggests there will be considerably more variation between the wastegate closed/wastegate open at equilibrium states.

Am I misunderstanding you or...?

DIRep972

iTrader: (1)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blundar &raquo;</TD></TR><TR><TD CLASS="quote">DIRep: I'll probably end up testing this myself, yes. I'm trying to get some idea of how much backpressure a T3/T4ish turbo generates once fully spooled and the majority of exhaust is bieng dumped out of a wastegate. </TD></TR></TABLE>

hehe, id bet it is alot. As the t3/t4 turbo's seem to overcome bad wastegate placement pretty easily.

blundar

I only said T3/T4 because they're marginally more common than my weapon of choice, and a .63A/R housing is roughly equivalent.

Full-Race Geoff

yes we are talking about the inverse of one another. I was referring to

exhaust
------------
intake

i expect your test to work much better with a restrictive (aka small) turbine housing than with our test. i think you would like the turbine housings we have been working on casting

Bailhatch

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Full-Race Geoff &raquo;</TD></TR><TR><TD CLASS="quote"> i think you would like the turbine housings we have been working on casting </TD></TR></TABLE>

with a nice, smooth WG dump dangling off it I hope? Someone needs to make that

popnbang

You will never find out what you want to know, unless you run the same exact
motor with the same exact load and temp. b.p. and so on.You can only get A ball park.

blundar

a ballpark would do... within 40% even...

Full-Race Geoff

i am making a turbine housing exactly for this to test on jeff evans' car

Arturbo

we'll be tesing exhaust back pressure with Ben Strader and Direp here very soon. We have everything set up with Autronic.

Boltz

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Arturbo &raquo;</TD></TR><TR><TD CLASS="quote">we'll be tesing exhaust back pressure with Ben Strader and Direp here very soon. We have everything set up with Autronic.</TD></TR></TABLE>

:drool:.... autronic...

Boostfed

We tested this on my T3 Full Race manifold and my T4 Full Race mani, Let me see if I can look up the #s. My old T3/60-1 .82 A/R was kinda high of course, the T4 different story. I will check and see if my tuner and machinist still have the #s.

Actually there is still a bung in the manifold prior to the turbine to check still, we can do testing next time on the dyno also.

blundar

even ballpark figures would be great, esp. for the t3/60-1.