lovehammer

Hey i was just wondering how much boost you guys are able to get with your turbos. i was watching a street racing dvd (techademics Mischeif vs. dynasty) and some guys was running his m3 on a dyno and was able to get 45 pounds of boost. are any of you guys even close to that.

cws T/A

iTrader: (3)

its not needed when 20psi is 1000hp

RyanJ

Boost is not good, its bad...its a restriction. Air flow is good. Making X psi is just dumb..especially 45psi. Although that's low for a diesel

ty_ty13

iTrader: (42)

PSI as said is just showing the motors restriction.... you want a lot of CFM with little boost...



that m3 might have made 1000rwhp when a LSx motor with 15# can make 1000rwhp...

PSI is a very irrelivant term and means nothing CFM is where power is made.

Reckless

iTrader: (9)

Yeah....why 45 psi when you can run 7.8's with 13 psi

GrahamHill

iTrader: (6)

Build a restrictor plate between the TB and manifold and I bet you could run all the boost you wanted to brag about, lol.

ty_ty13

iTrader: (42)

i like the sound of that

JZ 97 SS 1500

iTrader: (2)

Correct, boost is just a bragging #. Means nothing for hp.

As for diesel, that is correct. Our street truck runs 60+psi, our customers compound trucks vary from 90 to 130psi and our compound tractors run 230+ psi of boost. Here is another good video of what big boost looks like.

Big boost diesel

Jose

Pro Stock John

iTrader: (34)

With a smaller displacement engine, you had to lean on it to make big power. If you had a 2 cylinder engine, and wanted to make 800rwhp, you might end up hitting 30-40 psi since you would need to triple or even quadruple the total power.

obZidian

iTrader: (2)

how much boost is that monster running? engine forged mods?





...oh, can you say, turbo lag?!!
That was the coolest **** i have seen all day!!!

JZ 97 SS 1500

iTrader: (2)

That truck is stock crank, stock rods, LOW compression pistons and girdle. Boost is around 80-90psi.

Jose

99SS-T

iTrader: (5)

Ya thats some sick lag lol. How much PSI are those 2 trucks runnin and how much power? Definatly sick.


John

JZ 97 SS 1500

iTrader: (2)

They are around 1000+hp. The cummins engine is a remarkable beast.

As for the lag, yes it does take a bit to get them spooled, but also part of the time at the line is feeding fuel to the engine to create heat. When you run a pulling engine with extremely low compression you don't have enough heat and you put the flame out. Thats why sometimes you have to crank them with some ether to get them to light off. Diesels truely are awesome. We are working on twins for our daily driver shop truck now. We plan to reach 1000rwhp or so with meth and nitrous...hehe. Also you can take a stock crank and shave 40-60 lbs off of them, go with a 12V manual motor with billet cams and smaller rods and turn close to 7000rpms with them...

Jose

Fire67

iTrader: (3)

That I would really like to see. I couldnt imagine what those things sound like at 7,000 rpm
Considering the normal diesel the average joe would have in his truck only turns what 3,000?

JZ 97 SS 1500

iTrader: (2)

That is right, the stock cummins is done around 3000rpms. We are working on some duramax's now to make 700+rwhp and spin to 6500+ rpms as well. Right now the biggest problem is turbo location and sizing, but we are working on that also.

Jose

TrakDay

iTrader: (7)

Well like everyone else has said... boost is simply a measure of restriction. Hell I am trying to keep the boost around 15psi on my blower setup. Gotta keep the heads down!

DeltaT

iTrader: (5)

I suspect that at least 25 of those pounds were complete fantasy bullshit.

Jim

BIG BAD BLACKSS

iTrader: (4)

Junk, look at the scandalous DVD or the one out of NY forgot the name. Thats where the fast cars are. Oh and maybe a small handful of fast cars in houston or detroit.

engineermike

Most of you guys are right, but for the wrong reasons.

Boost is measured in the intake manifold plenum. So, if you manage to improve the intake port, runner, or cam timing, the boost pressure will decrease for any given compressor speed.

HOWEVER, with an intake port/runner/valve with zero restriction, you still want positive pressure because you are trying to get a higher density gas into the cylinder. Ideally, you would have 20 psi boost and the very same 20 psi of pressure in the cylinder at BDC before the intake stroke. 20 psi air has over twice the oxygen than atmospheric pressure air.

I, personally, want boost in the intake. If I'm good, then my heads and intake will get me full boost pressure in the cylinder also.

Mike

chuntington101

depends on what your running!!! you try geting a 2.0ltr Evo engine to make 700bhp at 20psi! noe with forged internals, cams, turbo, intercooler, stnadlaon, etc, etc oh and 45psi and you can see 900bhp at the wheels!

now on a V8 when you have atleast 2.8 time the capactiy you will never need that much boost to get the power!

but 45psi is nothing on a gas engine! bck in the 80's (when turbo tech was nothing like it is today!!!) they were running around 90psi and making 1500bhp on the dyno

oh and thats from a 1500cc engine

and dont top fuelers run about 45psi and they are making over 6500bhp

thanks Chris.