T-3 Super 60 Dyno numbers using JWT ECU program

[Nismo_Freak]

for all those that are reading this thread and believe that by putting in a JWT ecu, Enthalpy ecu or whoever decides to tune ecu in the next few years, that you can put whatever turbo on your car and the air fuel ratios will be the exact same as before, please dont believe it cuz you will yield different results.

the constant variable: boost

lets say you have a mafs system with T25 at 2.5v of airflow. then you have mafs system with a T70 at 2.5v of airflow.

what is gonna be different about these two? rpm at which its provided

fueling is applied according to mafs voltage (load) vs rpm so the fuel % value would be different for the given 2.5v of airflow.

and yes, JWT does dyno tune cars. they dont put Clark in his little room and expect him to guess or simulate what everyone is running. the dyno tune with certain turbos and expect the client/customer to use that or something very alike which wouldnt throw the air fuel ratios off base. so with that in mind, JWT didnt as well dyno tune their 50lb/cobra mafs program with a t3 turbo.

2.5 VOLTS = 2.5 VOLTS = THE SAME AIRFLOW

You use the same amount of fuel for the same amount of airflow! The ECU cannot enrichen the mixture! So, as long as the GT1000 Pratt-Witney turbo you run on the car pulls the same amount of air as the GT12 you were running before the resulting amount of fuel injected is the SAME.

You are thinking on the basis of a MAP system where the system measures absolute pressure and not FLOW.

Stop saying "I have no credit in this arguement" and actually sit down and THINK about what I am saying.

[Nismo_Freak]

so you are saying that putting a GT40R and running it at 7 psi would yield the exact same air fuel ratio that a car ecu's was originally designed to run at 7 psi on a tiny *** T25 turbo (flat line 12:1 for example and assuming neither mafs or injectors maxed out)?

No ... yet again.

7PSI T25 =/= 7PSI GT40R

What we are saying is ... 20 LBS / Min. flow = 20 LBS / Min. flow regardless of the size of the turbocharger!

If you have 20 LBS of air flowing through your motor at a 12:1 ratio is it incorrect to assume that 20 LBS of air flowing through your motor will again result in a ~12:1 ratio?

The factorization here is efficiency which yeilds slight deviations if any in A/F!

[virus77]

Im gonna have to say timing definatly changes the A/F ratio. If you have ever made timing chages through the powerband and datalog the A/F you will see this happen. Also 7 psi out of a gt40R flows considerably more than 7 psi from a t25. If you ran a GT40 at 3-4 psi and a t25 at 7-9 psi and the both had the same airflow it would yeild the same A/F

I wonder how low the A/F went. It goes off the chart so you really cant tell. If its around 9.X then you could say that it the JWT program running richer than normal due to the slight variables, but the power dropoff is pretty intense. It might just be a horrible tune.
Modified by virus77 at 5:18 PM 5/23/2005

[WDRacing]

For the record, changing your timing does change your AF mixture. Not by much, but it does change. Usually in the .5 region for several degree's of advance or retard.

This is a good discussion guys, keep it going.

[mikesloud]

I had same problem, the issue is the impedance difference btween 550cc and 50lb msd tha jimwolf tunes for , that is throwing it off, getr your msd's in there and should fix it .

[WDRacing]

Really? What is the difference? Post up some info, I'm interested.

[Nismo_Freak]

I had same problem, the issue is the impedance difference btween 550cc and 50lb msd tha jimwolf tunes for , that is throwing it off, getr your msd's in there and should fix it .

Hey Mike, def. check out our local board.

http://www.texas240sx.com

[Jeff240sx]

2.5 VOLTS = 2.5 VOLTS = THE SAME AIRFLOW

You use the same amount of fuel for the same amount of airflow! The ECU cannot enrichen the mixture! So, as long as the GT1000 Pratt-Witney turbo you run on the car pulls the same amount of air as the GT12 you were running before the resulting amount of fuel injected is the SAME.

I'm going to have to dissagree here. 2.5v at 3000rpm from a t25 and 2.5v at 3000rpm from a t88 are the same fuel. However, Klattr oversimplified things in this thread, which is why I disagreed. But he's not just saying a turbo switch will do it. He's talking about the increased airflow (I know.. airflow alone changes a/fs) and the shift in powerband. The ECU fuel map is topographical. 2.5v@1000rpm is very different than [email protected] course a change in airflow from a larger turbo will shift a/fs, but only because more of the fuel is used and more power is made.For this to be a discussion, and not a giant arguement, all but 1 variable has to be fixed.If airflow, rpm and horsepower are all fixed, the only variable would be turbo size. That would require different boost levels to retain the same airflow and horsepower. It is now when the turbo choice has no effect on the a/fs. However, when Klattr said "change in turbo" he implied "and the additional boost and rpm shift that comes with it". This is where I popped into this thread.Timing will change a/fs. I didn't know it would be a magnitude of .5 (WDRacing). But it would allow more/less time for the air:fuel mixture to burn, resulting in running richer or leaner when using the same ammount of fuel.Again.. this discussion is nothing when implicitly changing 2 or more variables.

Also, 550cc injectors and MSD 50# injectors have the same impedance as far as I know. While I have seen peak-and-hold 50# MSDs, I own the saturated type, and I believe most other 240 owners do also. 550cc I've never seen as peak-and-hold. Shouldn't be an impedance issue. If you try to run peak-and-hold injectors without those resistors, you'll cook the injectors. This guy has been running for a year, so I'm sure that's not his issue.-Jeff

[240SicknessX]

fastpace, do you know what your base fuel pressure with the vacume line dissconnected is? A friend of mine installed a walbro 255 in his car and his base fuel pressure w\ vac line off jumped from 43.5psi, to 60psi. This could be something that would promote the rich condition.

[Jeff240sx]

fastpace, do you know what your base fuel pressure with the vacume line dissconnected is? A friend of mine installed a walbro 255 in his car and his base fuel pressure w\ vac line off jumped from 43.5psi, to 60psi. This could be something that would promote the rich condition.

This is exactly what I meant by his fuel pump outflowing the regulator. This happens alot with older regulators.. haven't heard of it so much with the s14s. -Jeff

[Nismo_Freak]

But he's not just saying a turbo switch will do it. He's talking about the increased airflow (I know.. airflow alone changes a/fs) and the shift in powerband.

No he's not.

Go back to his Dyno post and read his post. He specificially points out the two A/F curves for the two nearly equal power outputs.

A/F ratios for equal flow should not variate by alot. While the map for the injectors is topographical like you said, it is that way because of the fact that between 6000 RPM's and 2000 RPM's you have changes in engine VE. This brings detonation into the equation because a higher VE results in higher cylinder pressures, thusly fuel and/or timing may be trimmed for detonation resistance.

[klattr1]

No he's not.

Go back to his Dyno post and read his post. He specificially points out the two A/F curves for the two nearly equal power outputs.

the comparision i made were between two turbos at the same boost level. t3/t04e at 17 psi, precision SC61 at 17 psi. you can notice the 22 rwhp gain just from putting the turbo on (same boost, same ecu, same injectors, same everything, etc)

oh yea and BTW, it would take ALOT of timing difference to change the air fuel ratios on a car (extreme situations especially like a 2-step would). ive been to dyno with 10 deg. advance and the air fuel plot was exactly same as before (maybe .3:1 afr offset in a few places). ive also experienced no changes in air fuel ratios by offsetting the base timing in other cars (SR20, DSM with DSMLink, etc)

[Jookmasta]

timing definitely affects a/f but can truly and only b seen by datalogging. as for the dyno results, congrats on the numbers but ur A/F's need some serious attention. I think i will have to go with the previous suggestion and see if trying to use the top feed injectors will correct the issue. also what mani are u running?

last but not least, does ur car idle? it would be great to see ur a/f's at idle cuz if ur rich like that in boost, i can only imagine at idle. Call Jwt asap and tell them ur issues. U should be producing alot more power than that at the lower boost level and for five hundred dollars worth of ecu, i would hope you could yield an a/f of at least eleven...............

[fastpace]

timing definitely affects a/f but can truly and only b seen by datalogging. as for the dyno results, congrats on the numbers but ur A/F's need some serious attention. I think i will have to go with the previous suggestion and see if trying to use the top feed injectors will correct the issue. also what mani are u running?

last but not least, does ur car idle? it would be great to see ur a/f's at idle cuz if ur rich like that in boost, i can only imagine at idle. Call Jwt asap and tell them ur issues. U should be producing alot more power than that at the lower boost level and for five hundred dollars worth of ecu, i would hope you could yield an a/f of at least eleven...............

The car idles fine for the most part. At times it will bounce around from 200-700 rpm and then as i push on the gas it would be fine. I called jwt today and they said that the injectors from 550 to the 50lbs are enough difference to make for a bad a/f ratio and also they told me that I would need to check my fuel pressure to see where it is at, they suggested if it is higher than 43.5 psi I would have to get another one or purchase an adjustable one. I don't know if I have posted it before, but I have a leak in my bov also. They told me that I would have to send in my ecu back to them and also provide one of my PE 550cc injector so they can flow test it and put it in there system. The total cost would be $130 bucks and would take "a couple of weeks". I am leaning towards this option and fixing the other problems with my turbo setup because I did originally was going to run the 50lbs setup.

[Jookmasta]

well that option seems a bit cheaper than buying a new fuel rail along with new injectors. as for the down time, u gotta get hit sumwhere. the bov leak definitely doesnt help the situation either. whats ur vac reading?

[toki]

the terms are "pressure" and "volume" guys. get with scientific conventions of the last 100 years. :P

and since we are talking about hotwire MAFS specifically here, we have to think about if the curve (or line) of the effect air volume has on the system is linear or not, as well as the pressure. I guess in theory the more dense air should be transferring more heat from the wires, but in real world situations that trend of cooling may not be linear.

this is why you just use a damn speed density setup, cut out the s*** factor.

[fastpace]

the vac reads 600 mm/Hg at idle. Oh yeah, the car will be down for about two months anyways. I am doing alot of alittle stuff and maintence to it that would be best done at the same time. I have a daily driver that I will be using for the summer.

[DRIFTEADOR]

klattr1, the hp gain comes from more airflow. at 17 psi the sc61 flows more than the t3/t4. you're still thinking manifold pressure. with a MAP sensor, when you switch to a bigger turbo the ecu sees the same load, 17psi, so it makes no changes to fuel. thats why you need to retune for the specific turbo. with a MAF, the ecu sees a greater load if more air is entering the engine, even at the same boost pressure, so it adds more fuel. the reason why it looks like the afr is different on the dyno plot is because the dyno measures over time, not airflow. at whichever rpm point airflow is the same, fuel should be same (real close anyway). adiabatic heat can make a small difference from turbo to turbo since the MAFS can't measure density but with any decent intercooler the difference shouldn't be noticable.

[Jookmasta]

so it reads 600 at idle? isnt the norm -20 or around there for vac?

[DRIFTEADOR]

600mm Hg=~23in Hg

damn metric system