Just Off The Dyno

[202.3rwkw]

you are right wolverine. we put some time into it. the plazmaman plenum is one quality product. they are beautifully engineered and while they arent truly bolt on, they dont require to much in the way of re-engineering to make them fit.

while the car doesnt "hold" 14psi thru to redline i still like to quote the highest boost figure shown on the run as the turbo has still accelerated to 14psi during the power run. just in case you wondering for no reason at all.

only thing to do now is replace a dead clutch!!! some things are a labour of love!

but not the cheese grater type love...........................

g

[LTHLRB]

Both dyno sheets posted that have made 220rwkw odd are not holding that 14psi or whatever to peak power...

So... Peak power of 219rwkw was made on roughly 12.6psi and the other dude that made 220rwkw... That was on a shade over 10psi.

So yes.. hrmmmmm, either way its a power figure... Who cares, A real 220rwkw I'd expect a high 12 sec pass with a good driver.

200rwkw.. A low 13. Once again with a decent driver who can drive.

Im making 209.5rwkw on 11psi and thats about all i can make really. The tuner and i are confident that it will run into the 12s with decent tyres and a good driver. Or even in full street trim. Does that seem about right? last tiem i had 205.0rwkw and ran 13.1@105 but i could have done a 13 flat or 12

[dezz]

was it your brother that ran the 13.1?

[shanef]

fantastic power figure

but i must say this...dezz, your 33 looks like a boat...GET THAT SUSPENSION SORTED

[dezz]

fantastic power figure

but i must say this...dezz, your 33 looks like a boat...GET THAT SUSPENSION SORTED

lol.

[R31Nismoid]

Im making 209.5rwkw on 11psi and thats about all i can make really. The tuner and i are confident that it will run into the 12s with decent tyres and a good driver. Or even in full street trim. Does that seem about right? last tiem i had 205.0rwkw and ran 13.1@105 but i could have done a 13 flat or 12

well i went through 12.9 @ 109mph with 210rwkw.

And my car weights near enough to the same an an R33

[Munna1]

Vey impressive results id really like to see a back to back result with the stock plenum vs the plazma man plenum.

cheers

[RB SANDY]

well i went through 12.9 @ 109mph with 210rwkw.

And my car weights near enough to the same an an R33

hi what are the mods you had at the time and did you get a very good take off.

[202.3rwkw]

Vey impressive results id really like to see a back to back result with the stock plenum vs the plazma man plenum.

cheers

hi munna, here is the back to back dyno charts for you.

the biggest thing with the plenum is obviously the amount of intake length you can remove and and as a result the increased throttle response. we were able to also add a fair whack of igntion timing as well.........

glenn

[R33RWKW]

Great Results, I made 212.9rwkw@12psi - using stock turbo, SAFC 2, 3.5" Jasma exhaust etc... before all my upgrades last year.

[Sydneykid]

we were able to also add a fair whack of igntion timing as well.........

glenn

Hi Glen, excuse me if I am somewhat sceptical, but I have NEVER EVER seen a plenum change give more power on an RB25 until well over 300 rwkw.

Hence I am confused, please help me out here..........

You stuck a new plenum on it and made 17 rwkw more.

Do you have a comparison with just the plenum change, no retuning?

If not, how can you claim that the plenum change made 17 rwkw difference?

“A fair whack of timing” was added, is it possible that the timing change made the extra power?

Is the claim that the plenum “facilitated” the timing advance?

OR

Since the boost remains the same, then to make the extra power you would need more airflow.

But there was no mention of changes in fuel mapping.

Hence the “extra airflow” would result in leaner A/F ratios

Perhaps that’s where the power came from.

Do you have an A/F ratio graph, before and after?

Otherwise. I am left with the conclusion that the extra power came from leaner A/F ratios and advanced ignition timing and the plenum did nothing.

In regards to the claim for improved throttle response, have you actually measured the internal volume of the plenum and the pipework and compared it to the original (standard) plenum and pipework? Due to the extra volume in the plenum I think you may find that any difference in internal volume could have been achieved for way less cost by using intercooler pipework with the 120 degree bend at the throttle body.

cheers .

Edited July 31, 2006 by Sydneykid

[Evan_R33]

God damn everyone fire right up.

Just be happy for the guy and don't be jealous. the dyno charts are there he's not telling stories...

everyone is quick to jump on the attack when someone is just trying to share their experiences...

just accept it and move on... everyone talks shit like they know. ie the last post... but the charts are there so accept it and move on.

[dezz]

God damn everyone fire right up.

Just be happy for the guy and don't be jealous. the dyno charts are there he's not telling stories...

everyone is quick to jump on the attack when someone is just trying to share their experiences...

just accept it and move on... everyone talks shit like they know. ie the last post... but the charts are there so accept it and move on.

LOL

yeah. 'cause Gary has no idea what he's talking about...

[202.3rwkw]

Hi Glen, excuse me if I am somewhat sceptical, but I have NEVER EVER seen a plenum change give more power on an RB25 until well over 300 rwkw.

Hence I am confused, please help me out here..........

You stuck a new plenum on it and made 17 rwkw more.

Do you have a comparison with just the plenum change, no retuning?

If not, how can you claim that the plenum change made 17 rwkw difference?

“A fair whack of timing” was added, is it possible that the timing change made the extra power?

Is the claim that the plenum “facilitated” the timing advance?

OR

Since the boost remains the same, then to make the extra power you would need more airflow.

But there was no mention of changes in fuel mapping.

Hence the “extra airflow” would result in leaner A/F ratios

Perhaps that’s where the power came from.

Do you have an A/F ratio graph, before and after?

Otherwise. I am left with the conclusion that the extra power came from leaner A/F ratios and advanced ignition timing and the plenum did nothing.

In regards to the claim for improved throttle response, have you actually measured the internal volume of the plenum and the pipework and compared it to the original (standard) plenum and pipework? Due to the extra volume in the plenum I think you may find that any difference in internal volume could have been achieved for way less cost by using intercooler pipework with the 120 degree bend at the throttle body.

cheers .

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

[R31Nismoid]

hi what are the mods you had at the time and did you get a very good take off.

laggy t04e, thats about it

2.1 60ft... so it wasnt the best of launches either

[R31Nismoid]

Less restrictive pipework equals more ignition timing... interesting comment.

How do you know it was restrictive?

Did pressure test @ the turbo outlet and then again @ the plenum when it was in stock form?

If you didnt, there is no way to can make that claim.

I wanna see before graph with AFR and after with AFR.

[DVS-31T]

my stocker turbo was only good for 205 kw on 12.5 psi made dont have any more flow after that , (you seen how small the turbine wheel is on em )

[Sydneykid]

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

I would be more than glad to do the measurements. I assume that's 2.68 cubic metres, since there isn't 2.68 linear metres of pipework. That's a saving of 600 mm of 75 mm pipework. You could have saved more than that by going to the 120 degree pipework at the throttle body style. Like this;

The other check of effectiveness would be to do the numbers on the time taken for 2.68 cubic metres to travel through the inlet system. Let's use 1 bar and 3,000 rpm as basis;

2.5 litre engine running 1 bar at 3,000 rpm =

2.5 x 2 / 2 x 3,000 / 60 = 125 litres per second

So 2.68 litres = 2/100ths of second

Half that at 6,000 rpm (1/100th of a second)

That's not much improvement in throttle response

I am not sure that it is good value for money on a road car

Logic tells me any improvement felt in throttle response comes from the advanced ignition timing, rather than the tiny decrease in internal volume.

cheers

Edited July 31, 2006 by Sydneykid

[202.3rwkw]

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.

apoligises guys, i just did a comparison on datalogit. we have added just a bit of fuel across touched areas of map. sorry

[202.3rwkw]

I would be more than glad to do the measurements. I assume that's 2.68 cubic metres, since there isn't 2.68 linear metres of pipework. That's a saving of 600 mm of 75 mm pipework. You could have saved more than that by going to the 120 degree pipework at the throttle body style. Like this;

The other check of effectiveness would be to do the numbers on the time taken for 2.68 cubic metres to travel through the inlet system. Let's use 1 bar and 3,000 rpm as basis;

2.5 litre engine running 1 bar at 3,000 rpm =

2.5 x 2 / 2 x 3,000 / 60 = 125 litres per second

So 2.68 litres = 2/100ths of second

Half that at 6,000 rpm (1/100th of a second)

That's not much improvement in throttle response

I am not sure that it is good value for money on a road car

Logic tells me any improvement felt in throttle response comes from the advanced ignition timing, rather than the tiny decrease in internal volume.

cheers

sydneykid.

sorry i miss read you above post. the timing was definately a positive in the throttle response stakes. but the reduce pipework, in my mind, was a major contributing factor.

Edited July 31, 2006 by 202.3rwkw