Gen3 3SGTE Dyno Run, Guess my numbers! Options

[jgreening]

I have hard time understanding how you can increase flow without increasing the pressure? Isn't pressure directly proportional to flow? For example, if i get rid of an restrictive intake in favor of a short ram i will increase the flow -> flowing more air into the mani -> producing more manifold pressure ?? Enlighten me please

Because restrictions allow pressure to build more easily. When you remove a restriction, you will have more flow at the same pressure. Make sense?

[CilverSeliST205]

Because restrictions allow pressure to build more easily. When you remove a restriction, you will have more flow at the same pressure. Make sense?

I see, a restriction prevents pressure from escaping, therefore restrictions allow pressure to build more easily... Makes sense...

But isn't MAP + IAT sensors capable of precisely calculating the ammount of air molecules entering the combustion chamber ? fuel injection is adjusted accordingly pressure and temperature of intake air, how does more flow alter the ammount of oxygen entering combustion chamber per cycle ?
Sorry for bombing you with questions

[jgreening]

Because restrictions allow pressure to build more easily. When you remove a restriction, you will have more flow at the same pressure. Make sense?

I see, a restriction prevents pressure from escaping, therefore restrictions allow pressure to build more easily... Makes sense...

But isn't MAP + IAT sensors capable of precisely calculating the ammount of air molecules entering the combustion chamber ? fuel injection is adjusted accordingly pressure and temperature of intake air, how does more flow alter the ammount of oxygen entering combustion chamber per cycle ?
Sorry for bombing you with questions

I am not even sure the 3rd gen 3sgte uses a IAT sensor. However, to answer your question:

Pressure + temperature will get you density and mass if you know the volume. A map sensor would calculate pressure whereever the sensor is. A IAT would calculate temperature whereever the sensor is. If those items were in the same location and the volume was static, it would be possible to calculate the amount of air (mass) in that location. However, I am not sure those sensors alone (or even considering static displacement at a given RPM) would be enough to calculate flow. I am not sure of myself on this point.

[phattyduck]

But isn't MAP + IAT sensors capable of precisely calculating the ammount of air molecules entering the combustion chamber ? fuel injection is adjusted accordingly pressure and temperature of intake air, how does more flow alter the ammount of oxygen entering combustion chamber per cycle ?
Sorry for bombing you with questions

Actually, a AFM or MAF based system is MUCH better at measuring/calculating air flow into and out of the motor. (as it is measureing the actual mass (AFM) or flow (MAF) of the air going past the measuring device) MAP based ECUs are cheaper and allow for bigger power as their is no restriction on the intake for a measuring device.

A MAP+IAT based fueling system requires an assumtion of the volumetric efficiency of the motor (VE) to calculate theoretical airflow through the motor (volume of air sucked into each cylinder per intake stroke). Any time you do a modification that allows the motor to breath more easily (intake, porting+polishing, exhaust, turbo, etc.), more air flows through the motor at a give intake manifold pressure. Since the ECU has no easy way of knowing that the VE has changed, it assumes an incorrect airflow which leads to incorrect fueling which leads to possible *boom*

-Charlie

(so, lower exhaust back pressure means that more exhaust can escape through the exhaust ports, leading to more air being pulled into the cylinder on the intake stroke for the same manifold pressure... a better intercooler means that the there is less pressure lost across it so that the pressure at the outlet of the turbo is lower compared to the intake manifold - less boost at the outlet of the turbo leads to less exhuast back pressure at the exhaust ports (turbo doesn't work as hard) which leads to more air flowing though the motor at a given manifold pressure. get the idea?)

[CilverSeliST205]

Yes gen3 uses IAT but i ment MAT in place of that since IAT is just a boost cut safety device for cold days, and it sits close to intake air filter, while MAT is right next to MAP in the mani...


So you guys are saying that the 3rd variable in equation, VE, is proportional to the flow, makes sense thanks for words of wisdom! Well, if i see my A/F too lean for my liking, then I'm going to invest in safc/afpr and a wb o2, and do a little bit of richening up... or is this a better idea:
HKS F-Con

Well I will see after the dyno if I even need any of that since so far I see gen3 ECUs likes to run all rich on boost

[phattyduck]

Yeah, when I said "IAT" I really meant in the manifold. On non-turbo cars, a temp sensor at the filter is sufficient - on turbo cars it has to be after the intercooler somewhere...

I'm glad my hastily put together explaination was clear enough. You have a good plan - just check the AFR's and everything should be fine.

Good luck, and report those numbers back! (I'm interested since I will have the same setup soon...)

-Charlie

[Wolf_tm]

Must agree with jgreening...

EVERY 3sgte 3rd gen I have ever seen on dyno, with the same simple mods
( full 3" exhaust - boost at 1.2 bar - 17.6psi ), made ALWAYS a flywheel power from 280 to 290, so around ( calculating a 4wd average loss of 24% ) 225 to 235 4w hp...

And I must say that every time I see an US car dynoed, I always get amazed by the "fantastic" numbers...

the last one is a Celica T23 turboed by xxx, with stock internals, and 365 WHP !!!!!!!!!!

Mah... for sure in Italy, with same mods, we always get lower numbers... if cars are dynoed by the owners....

if the dyno is made by the mechanic/tuner, you're getting for sure number 20% bigger...

[CilverSeliST205]

Must agree with jgreening...

EVERY 3sgte 3rd gen I have ever seen on dyno, with the same simple mods
( full 3" exhaust - boost at 1.2 bar - 17.6psi ), made ALWAYS a flywheel power from 280 to 290, so around ( calculating a 4wd average loss of 24% ) 225 to 235 4w hp...

And I must say that every time I see an US car dynoed, I always get amazed by the "fantastic" numbers...

Yeah but in US we get smaller hp transfer loss because we don't use 4wd trannys.
Another thing is that dynojet will always give higher numbers than a most brake dynos, and dynojet got monopoly in usa

[Wolf_tm]

Yeah but in US we get smaller hp transfer loss because we don't use 4wd trannys.
Another thing is that dynojet will always give higher numbers than a most brake dynos, and dynojet got monopoly in usa

Ok, correct... I was in error for the "ST205" in your nickname,
I didn't realize you are going to have a 3SGTE with fwd ST202 gbox.

So the power I think you'll get, should be around 240 - 250 whp.

PS: pay attention on running those whp on ST202 box, the only one ST202-3SGTE engine-fwd we have here in Italy broke the gbox two times in 2 year.
Now he turned the boost back to stock - 240 flyhp = 207 whp

[CilverSeliST205]

Ok, correct... I was in error for the "ST205" in your nickname,
I didn't realize you are going to have a 3SGTE with fwd ST202 gbox.

So the power I think you'll get, should be around 240 - 250 whp.

PS: pay attention on running those whp on ST202 box, the only one ST202-3SGTE engine-fwd we have here in Italy broke the gbox two times in 2 year.
Now he turned the boost back to stock - 240 flyhp = 207 whp

Yeah I should have put SW20 instead ST205 in my nickname since my engine came from mr2t
Oh and I don't use ST202 tranny, I got mine from a v6 solara (E153) so i hope it will hold up better..
I would be happy to see 250whp dynoed... oh and isn't gen3 like 251-260 flywheel hp? or is your buddy running a gen2 ? either way 240fhp-207whp= 33hp loss= ~14%, not too much loss, but i would rather loose 24% and be awd

[Wolf_tm]

Cilver,

3sgte 3rd gen is claimed to have 242 cv = 245 bhp; dynoed stock it has 238/240 cv.

This same engine has 255 bhp in japan, only because their pump gas is 101ron.

If you'll use atf dexron 2 oil in your gbox, you won't have a tranny loss of 17%, but around 14%.

[CilverSeliST205]

Cilver,

3sgte 3rd gen is claimed to have 242 cv = 245 bhp; dynoed stock it has 238/240 cv.

This same engine has 255 bhp in japan, only because their pump gas is 101ron.

I did not know that, and now im glad i got jdm ecu
should i be glad ? is it producing more power because ecu allows more timing on 101ron ? or because different a/f maps are used on jdm ecu ?

If you'll use atf dexron 2 oil in your gbox, you won't have a tranny loss of 17%, but around 14%.

You are full of good info Wolf is there any disadvantage to using atf dextron ? will it be safe to use it on a daily driven car ? where can i get it ?

Thanks!

[Wolf_tm]

Cilver,

3sgte 3rd gen is claimed to have 242 cv = 245 bhp; dynoed stock it has 238/240 cv.

This same engine has 255 bhp in japan, only because their pump gas is 101ron.

I did not know that, and now im glad i got jdm ecu
should i be glad ? is it producing more power because ecu allows more timing on 101ron ? or because different a/f maps are used on jdm ecu ?

I don't think it depends on the ecu, jdm or not:
every T20 ecu is TCCS, the system that, after an ecu reset, controls the fuels you have in the tank, applying its original timing map ( more advanced, for Jap's fuels ) and then applying a retard trim till the ecu hears no more dets with the knock sensor... that's way, after a reset, the car seems to have a unusual behaviour...

If you'll use atf dexron 2 oil in your gbox, you won't have a tranny loss of 17%, but around 14%.

You are full of good info Wolf is there any disadvantage to using atf dextron ? will it be safe to use it on a daily driven car ? where can i get it ?

Me ? Good info ??
Someone else in the list told me I give "false informations" !!!! And I was just reporting what Engine Eng. Bells wrote on a book !!!!

I had those info from Saf: on his ST185's and his Supra's manuals it's written he can use ATF D2 in the gbox, and given that ST205 gbox is very similar, I followed his advice and use it for 80.000 kms even in my car with NO problems.
He says that it's not necessary to use an E.P. GL4 or GL5 oil in this kind of boxes...

ATF Dexron2 is a automatic trans/power steering oil... and it should be better if you find the old D2 instead of the new D3... changing gears is faster and lighter with this oil.
It's also very cheap.

Bye...

This post has been edited by Wolf_tm: May 17, 2006 - 2:23 AM