Just Off The Dyno

[The Dan]

To start with, why does everyone assume the stock turbo just pushes hot air around after 14psi. What a crock of shit.

What I would like to know is....how do you make 220rwkw using the stock AFM which maxes voltage at a required airflow of 210rwkw on that engine?

[Cubes]

To start with, why does everyone assume the stock turbo just pushes hot air around after 14psi. What a crock of shit.

Get one holding that boost pressureis the problem... Once you do then there's the issue of high backpressure dropping ve resulting in crap power anyway. Running in to choke (which they clearly do) heats air. Its not the boost anyway... As you know its the airflow at that boost level, 14psi on an rb20 is like 11psi on an rb25det.

What I would like to know is....how do you make 220rwkw using the stock AFM which maxes voltage at a required airflow of 210rwkw on that engine?

Once the afm hits 5.115v it will no longer drop to a greater load point. It stays on that load point and simply travels x along the rpm. You then tune those load points to achieve the afr and ign your after. Its not optimal as anything less than that boost level/airflow its going to run rich and less then optimal ign. timing.

Which isn't really too much of a problem for a turbo car as its difficult to hold partial boost levels at an rpm where the afm is likely to max out ~5000rpm. If you try to push say 300rwkw through the stock afm then its obviously going to crap its self as afr's are going to be mega rich as the afm initially max's out, it then has to get through the rich and less than optimal ign. timing until it reaches the airflow the afr and ign. are suited for.

[LTHLRB]

was it your brother that ran the 13.1?

Yeah, i was too scared and unexperienced to drive that day, finally grew the balls and ran 13.7@102, alot of hesitation with missing 3rd and backing off in 4th because the car jumped. I am still waiting to get more cash and then run it again when i am 18. Hopefully will run another pb and get the best time with me driving it. Id rather let someone with more experience do it than i do it myself and f**k up.

Edited July 31, 2006 by LTHLRB

[R31Nismoid]

To start with, why does everyone assume the stock turbo just pushes hot air around after 14psi. What a crock of shit.

What I would like to know is....how do you make 220rwkw using the stock AFM which maxes voltage at a required airflow of 210rwkw on that engine?

Some of you posts make me seriously make me wonder at times.

Things generally arent assumptions, i wouldnt make the assumption that they are either

[202.3rwkw]

On a humourous side note - a very well educated on all matters vehicular teacher of mine, who used to be the head trainer for toyota australia has a great saying -

"assumption is the mother of all f**k ups!"

just a thought

[paulr33]

im so with ash 100%

[GTAAAH]

^^

Edited August 3, 2006 by r32 gts-turbo

[Munna1]

sydneykid,

i do apoligise that i dont have a "as driven" unretuned dyno ramp for it. i am the first to agree that an aftermarket plenum CAN be a waste of time. A GReddy manifold on an sr is an often quoted mismodifiction.

i will also be the first to tell that that with no extra timing added to the maps that this would have been a grandeous waste of the time.

the power we made with the plenum came from timing added. we were able to add the timing to less restrictive pipework, shorter intake and the cooler intake charge that is a product of this. simple as that.

we have also been able to pull out a little fuel and still been able to maintain a safe detention barriar. so yes the power came from timing and fuel changes. the plenum faciltated this.

the reason the plenum was added was to facilate the changed pipe style setup. i measured the removed pipework at 2.68metres. you can make your decisions re throttle response by adding that much to ur existing setup and getting back to me..........

cheers

Interesting discussion guys keep it up.

So am in correct in stating that due to the shorter piping length and the efficiency of the new penum the intake tempurature was dropped which allowed for the extra timing ect?

I find it hard to belive that the shorter piping would make that much difference to the heat of the air as it is moving extreemly fast. So there would not be enough time for it to get any hotter. (please correct me of I am wrong)

So is it mainly to do with the extra effency of the plenum (easier for air to get into the engine) that equates to less heat been generated hence timing can be advanced?

[paulr33]

no what it means is that the extra gains came from the advanced timing that was done on the tune level. it is likely that the plenum changed achieved zero.

[Munna1]

But I think he was saying that when it was stock if as much timing was put in it would ping due to heat.

[Cubes]

Just looking at the dyno graph...

Your turbo appears to spool slightly later than I've seen other r33's.... ~3200rpm for 12psi..

On the dyno I run on, loaded up in fourth they generally hit 12psi ~2700rpm.

Is there an OP6 stamped on the turbine housing by any chance?

This could explain why its making decent power as the R34 turbo's generally make up to ~10rwkw more than the r33 turbo's.

[r_speedfreak_r]

i'm probalby wrong but im kinda stunned that no one can belive the stock turbo can handle more than 12 pound. i know the series 1 turbos couldnt handle high boost but the series 2 turbo has stronger internals and i've heard of people running huge power with the stock series 2 turbo. even if you just browse through the section on the forum where people post there mods and dyno outputs there are heaps of people on there that purchase bigger turbo but then they dont have the fuel system to go with it so really there not putting out huge numbers either. there are plenty of 33's with smart mods but stock series 2 turbos that put out good street power.

[rob82]

Just looking at the dyno graph...

Your turbo appears to spool slightly later than I've seen other r33's.... ~3200rpm for 12psi..

On the dyno I run on, loaded up in fourth they generally hit 12psi ~2700rpm.

Is there an OP6 stamped on the turbine housing by any chance?

This could explain why its making decent power as the R34 turbo's generally make up to ~10rwkw more than the r33 turbo's.

Has more to do with the ramp rates and how many graphs the computer that runs the dyno has on it. If there are too many files it takes a second or two to start the ramp however the car is already accelerating

so it draws a shite graph and the boost comes on slower as there is less load. Shootout is so crap - this is one of the many reasons I dont tune in shootout.

[Munna1]

i'm probalby wrong but im kinda stunned that no one can belive the stock turbo can handle more than 12 pound. i know the series 1 turbos couldnt handle high boost but the series 2 turbo has stronger internals and i've heard of people running huge power with the stock series 2 turbo. even if you just browse through the section on the forum where people post there mods and dyno outputs there are heaps of people on there that purchase bigger turbo but then they dont have the fuel system to go with it so really there not putting out huge numbers either. there are plenty of 33's with smart mods but stock series 2 turbos that put out good street power.

Ive never heard that the s2 r33 turbo has stronger internals than the s1 I thought the weekest point on both turbos was the ceramic wheel which fails if to much heat is generated. As far as I was aware the only real difference between these turbos was the nylon compressor wheel which would not make the turbo stronger but does reduce lag. But please correct me if I am wrong.

Edited August 2, 2006 by Munna1

[GTAAAH]

Oops haha, i read this whole topic with interest, amazed that a rb20 with light tuning could put out 200rwkw... I just now realised that its a topic on r33's haha swear i red r32 some where..Too many things kill brain cells

Edited August 3, 2006 by r32 gts-turbo

[Roy]

no what it means is that the extra gains came from the advanced timing that was done on the tune level. it is likely that the plenum changed achieved zero.

Im seriously considering one of these plenums and it seems there has been a few ppl make these sort of numbers when using the Plazmaman plenum.

If the extra power came from the advanced timing, why arent all R33s with PFcs making the same power as this one?

[Devils_Advocate21]

God damn now thats brinigng up an old topic Timing and i believe we never saw any afr's on this dyno that this guy produced , Oh and ic piping doesnt mean crap, as for one air is present at all times in molecular form, if you blow through a straw its not the air coming out your mouth first its the air present before hand hitting your fingers. The advantages of the plenum can come from a number of things aswell, esp in the design of it. and to answer why arent all r33's making the extra power with the advanced timing, is becoz not all r33's are the exact same right down to the tiniest thing, and different dynos, different factors, different alot of things.

My opinions

[Roy]

With a Pfc you can only tune to the max of the weakest link.

Why is it so hard to believe something that with some aftermarket clevers applied to something for a performance application (something Nissan werent thinking with the RB25. It was the poor cousin to the RB26, hell even the RB20 at one time was the premier performance engine for touring car racing...same cant be said for the RB25 so)

If the thing flows a bit better, flows more evenly and is better at equalising cylinder filling across all cylinders...doesnt it stand to reason that a "weaker" cylinder will not ping earlier then the "better" cylinders...maximising the effeciency of the engine?

Sure engines are different and dynos are different....but to date every car i have seen with this particular plenum has had better then expected results...so it kind of bucks the engines are different, dynos are different. The one definite thing different is the plenum and they seem to make a bit more power on a small crappy turbo

Im a cynic, but an open minded cynic

[FineLine]

My credentials....Nil. My logic..... Roy owns it.

[GTshortie]

Best way to find out if the 220rwkw is true is take it down to the track it should achieve high 12's - low 13 no problems or at minimum a 110+mph trap speed.

Interesting results for stock turbo though (if it is a stock 33 turbo)