3 Simple Questions About Increasing Boost On An R33

[Dajae]

Agreed, was just wanting to illustrate the point in understandable terms, for the masses.

[GTScotT]

Either way, like I said - if all the other variables are in check the boost figure is far from the most important thing.

Variables such as; what turbo, what fuel......... etc.

[89CAL]

Buy this-

http://www.ebay.com....d#ht_2967wt_905

Then do this-

I done it to mine and have exactly the same mods as u except i have a blitz cooler, the power increase is noticable. Run 8-10psi.

Cheap and easy.

Dont bother with the turbosmart one. Turbotech ones are cheaper on ebay and work really well.

If you want to spend $50 on a turbosmart boost controller I'll sell you my dual stage, but Seriously I would just do the high boost mod so it runs 7psi all the time and leave it at that till you get an aftermarket ECU. I've been there, done that.

[ausdrift]

Yeah, ive done the high boost trick (though not 100% sure it worked as the stock guage is stuffed and I never bothered to get an aftermarket one) and Im thinking maybe ill just stick with that for now. Instead I might just buy an electronic boost controller and bring it back with me to fit later, and get it tuned, etc etc

[blk94r33]

Boost is a measurement of pressure.

Pressure is a measurement of flow against restriction.

Turbos FLOW air, the pressure is created by the engine restricting that flow.

10psi=10psi. A different turbo at the same "boost" is flowing the same amount of air, provided EVERYTHING else is left the same, ie. cams, valves, ports, manifolds, throttle body, piping, intercooler.

People get confused about different turbos making more power on the same boost. It isn't flowing more air into the engine, but is more efficent at using the exhaust flowing out and makes other gains to make more power.

If you get a 100kg guy and a 50kg guy to blow up an identical balloon to say 1 psi, they have both put the same amount of air into the balloon.

EDIT:http://passionford.com/forum/technical-essay-archives/843-how-a-big-turbo-makes-more-power-for-same-boost.html

Edited February 1, 2012 by blk94r33

[JonnoHR31]

Boost is a measurement of pressure.

Pressure is a measurement of flow against restriction.

Turbos FLOW air, the pressure is created by the engine restricting that flow.

10psi=10psi. A different turbo at the same "boost" is flowing the same amount of air, provided EVERYTHING else is left the same, ie. cams, valves, ports, manifolds, throttle body, piping, intercooler.

People get confused about different turbos making more power on the same boost. It isn't flowing more air into the engine, but is more efficent at using the exhaust flowing out and makes other gains to make more power.

If you get a 100kg guy and a 50kg guy to blow up an identical balloon to say 1 psi, they have both put the same amount of air into the balloon.

EDIT:http://passionford.c...same-boost.html

your forgetting one critical factor, temperature. a bigger turbo at the same boost level is flowing more air due to lower temps and usually less exhaust restriction aswell. by your theory you could take a 300rwkw motor and bolt on a standard rb25 turbo, changing nothing else and it should still make 300rwkw at 18-20psi boost, never gonna happen.

[GTSBoy]

<br />Boost is a measurement of pressure.<br />Pressure is a measurement of flow against restriction.<br />Turbos FLOW air, the pressure is created by the engine restricting that flow.<br /><br />10psi=10psi. A different turbo at the same "boost" is flowing the same amount of air, provided EVERYTHING else is left the same, ie. cams, valves, ports, manifolds, throttle body, piping, intercooler.<br /><br />People get confused about different turbos making more power on the same boost. It isn't flowing more air into the engine, but is more efficent at using the exhaust flowing out and makes other gains to make more power.<br /><br />If you get a 100kg guy and a 50kg guy to blow up an identical balloon to say 1 psi, they have both put the same amount of air into the balloon.<br /><br />EDIT:<a href='http://passionford.com/forum/technical-essay-archives/843-how-a-big-turbo-makes-more-power-for-same-boost.html' class='bbc_url' title='External link' rel='nofollow external'>http://passionford.c...same-boost.html</a><br />

<br /><br /><br />

And you also forgot that if the car is making more power (let's say quite a bit more power, not just the extra you'd get from slightly better efficiency) then the bigger turbo is definitely blowing more air into the engine. What the real difference is is that the bigger compressor comes with a bigger turbine section (generally, mismatched abortions not counted) and so there is actually less restriction on the back side (compared to the smaller turbo). So for these two turbos, the same boost is seeing more restriction through the back of the little turbo and less restriction through the back of the big turbo, and so more gas flows through the big one.

Same argument, just stated more correctly.

[Bronx]

hmmm, on my first stock r34 turbo, i hit 17psi before i blew an oil seal. really upsetting, but i ran that for 2 years.

now i decided to run lower and only hit 14psi. but this r34 turbo has that crappy plastic front wheel, which my other one didnt have. so im afraid of going higher.

the first one i ran on my stock ecu, and it hit fuel cut at 16psi. changed to power fc and works fine.

now run 14psi with stock tune on power fc, walbro fuel pump, split dump with 3" exhaust.

NOOOOO clue on how much power i make, too poor to afford a dyno run

[blk94r33]

<br /><br /><br />

And you also forgot that if the car is making more power (let's say quite a bit more power, not just the extra you'd get from slightly better efficiency) then the bigger turbo is definitely blowing more air into the engine. What the real difference is is that the bigger compressor comes with a bigger turbine section (generally, mismatched abortions not counted) and so there is actually less restriction on the back side (compared to the smaller turbo). So for these two turbos, the same boost is seeing more restriction through the back of the little turbo and less restriction through the back of the big turbo, and so more gas flows through the big one.

Same argument, just stated more correctly.

Better way of putting it.

I don't get when someone says 10 psi somehow is different to 10psi. If the volume/restriction INTO the engine hasn't changed, then 10psi is still the same amount of air. I'm not denying that a bigger turbo makes more power, just that it doesn't somehow miraculously change the VOLUME (not factoring in density/temperature) of the air into the engine....

[blk94r33]

your forgetting one critical factor, temperature. a bigger turbo at the same boost level is flowing more air due to lower temps and usually less exhaust restriction aswell. by your theory you could take a 300rwkw motor and bolt on a standard rb25 turbo, changing nothing else and it should still make 300rwkw at 18-20psi boost, never gonna happen.

That's a completely different kettle of fish. Stock turbo will never make 300rwkw due to that much air being way out of it's efficiency range and the exhaust housing would never flow enough etc. etc.

If you have an identical size cylinder say 100L, and a 1/8 inch line leading into it, PLEASE explain how a bigger "compressor" will fill that cylinder quicker (increase in flow/volume) at the same INLET PRESSURE with nothing else changed?

As above, the gains for a larger turbo are from temperature differences and lower restriction on the exhaust side, as well as the turbo simply being more efficient at processing air in/out.

[Dajae]

Have you ever used a large scale air compressor? Compared to a small one?

Both run at 120psi. The small one flows 500cfm through a 1/4 hose. The large one, still at 120psi flows 1500cfm through a 1/4 inch hose.

How can you possibly say the volume stays the same?

As you said, boost is a measurement of restriction, not volume. Unfortunately you HAVE to factor in temp of the discharged air (compressor side). 10psi will always be 10psi, this is simply the fact of the matter.

But the volume will changed.

Think of two bottles. One is 500ml capacity, the other is 2L capacity. Both are filled to 10psi pressure.

The pressure is the measurement of the forces acting against the enclosure. However, the 2L bottle will be holding a substantial amount of air. Therefore, a larger compressor will be able to push more VOLUME.

Discuss if you disagree.

Ty.

[JonnoHR31]

That's a completely different kettle of fish. Stock turbo will never make 300rwkw due to that much air being way out of it's efficiency range and the exhaust housing would never flow enough etc. etc.

If you have an identical size cylinder say 100L, and a 1/8 inch line leading into it, PLEASE explain how a bigger "compressor" will fill that cylinder quicker (increase in flow/volume) at the same INLET PRESSURE with nothing else changed?

As above, the gains for a larger turbo are from temperature differences and lower restriction on the exhaust side, as well as the turbo simply being more efficient at processing air in/out.

exactly, and what happens when you go past a turbos normally efficieny range? shaft speeds go up and heat goes up exponentially, so the inlet charge from a stock turbo at 18psi is gonna be a hell of a lot hotter than a gt35 at 18psi. Hot air is less dense, therefore the bigger turbo is flowing more air at the same boost level. This will apply at almost all boost levels but it becomes more apparent at higher boost levels.

Again the bigger compressor will pump more efficiently and therefore put less heat into the inlet charge, cooler air is denser.

Yes, the gains are from temperature and lower restrictions, but as you'd hopefully know temperature changes the density of air, cold air is more dense, hence why an intake charge at a set pressure is going to flow more air the colder it is. Bigger turbo, cooler intake charge, cooler charge, more dense air, more dense air more airflow at the same boost and therefore more power.

[joeyjoejoejuniorshabadoo]

what i got from that link is that the passionford boys seem think there were only ever two types of turbo's produced... "T3" and a "T4"

[GTSBoy]

I don't get when someone says 10 psi somehow is different to 10psi. If the volume/restriction INTO the engine hasn't changed, then 10psi is still the same amount of air. I'm not denying that a bigger turbo makes more power, just that it doesn't somehow miraculously change the VOLUME (not factoring in density/temperature) of the air into the engine....

It does change the volume. As per my last post, the restriction IS different. The flow system (after the compressor outlet) consists of the engine AND the turbine section of the turbo. The engine stays the same, so it's contribution to the total restriction stays the same, but a bigger exhaust section on the turbo means less restriction. With less restriction in the flow system you must flow more air to maintain the same back pressure (boost).

[Bsa]

Boost is a measurement of pressure.

Pressure is a measurement of flow against restriction.

Turbos FLOW air, the pressure is created by the engine restricting that flow.

10psi=10psi. A different turbo at the same "boost" is flowing the same amount of air, provided EVERYTHING else is left the same, ie. cams, valves, ports, manifolds, throttle body, piping, intercooler.

People get confused about different turbos making more power on the same boost. It isn't flowing more air into the engine, but is more efficent at using the exhaust flowing out and makes other gains to make more power.

If you get a 100kg guy and a 50kg guy to blow up an identical balloon to say 1 psi, they have both put the same amount of air into the balloon.

EDIT:http://passionford.com/forum/technical-essay-archives/843-how-a-big-turbo-makes-more-power-for-same-boost.html

You can't be serious take all the boost out of it if you get two fans put them side by side and stand in front of them the big fan will flow more air then the smaller one it's same going for compressor wheels if you have a stock comp wheel against a gt30 wheel the gt30 comp wheel is bigger and will flow more. On my 20 the rb25 turbo got me 170 kw at 14 pound then I installed a td06 and made 220 kw on 14 pound the motor didn't decided oh yay new turbo I'll make power now it's the fact the td06 flowed heaps more for the same boost

[Dajae]

So to the OP, have fun reading

[Bsa]

Kinda got out of hand in this post

[blk94r33]

So according to this theory, fitting a T04Z to an absolutely standard RB25 and running it at 10psi will yield 800hp because it can flow 11ty cfm?

[GTSBoy]

So according to this theory, fitting a T04Z to an absolutely standard RB25 and running it at 10psi will yield 800hp because it can flow 11ty cfm?

No, but it will try. The engine will break, but the turbo will certainly try to work exactly the same way as it would on an engine that had been built to survive 800HP worth of boost and stress.

What were you expecting?

[blk94r33]

How?

You can run the biggest turbo you want, if the actuator is only set-up to run 10psi into the inlet system, then the turbo will only FLOW enough air into that restriction to make 10psi. It can't cram 10 times the volume of air into the same engine without increasing the pressure?