Dyno # HELP!!!

[Jadesr20det]

Ok so a few weeks ago I went to a local dyno day to see where my SR was at. Me and my friend had hooked up a gauge as well as MBC into the car. At that point the gauge reflected that I was running at 14lbs (exactly where I wanted to be). Problem is I did 3 pulls the first 2 of which were absolute trash netting 165 WHP and 238 TQ. Now the problem lies in the fact that my FPR wasn't hooked up (which I have since fixed) and the A/F was skyrocketing to 18 A/F. Mind you also that the dynojet also showed that I was 16lbs of boost. So I changed everything back to stock settings and pulled 220WHP and 200TQ healthy #'s yes but I miss the pull (since I'm on the SR forum I know I don't have to worry about any KA-T guys comments *wink*). So my question after my babbling is I have the NEO and was figuring will I have to tune out the A/F to correct it for 14lbs? I have never heard of neone having to do this. Or was it maybe cuz my FPR was not connected if that is what was causing the trouble. Pleez help as I wanna put the t25 back up to 14 as I'm at 5lbs now I belive my actuator is maybe at the end of days.

Mods:Redtop SRT25 turboFMIC3 Inch Exhaust255 WalboroEverything else stock.

Thanx in advance and srry for the long *** post

[DrifterProdigy85]

Stock boost should be 7psi on the T25 Actuator. Either your gauge or wastegate is bad. Also you shouldnt have to do anything to tune for higher boost. Thats the purpose of the MAF. As it senses more air being drawn in, it increases fuel. Without your FPR being plugged in, you were most likely running lean from that. My advice is to get a Nismo FPR and set fuel pressure to 43psi (vacuum disconnected), Boost Leak IC Pipes, and dont **** with the SAFC untill you get a wideband to do so. 220whp on stock boost is pretty damn good. You will definitly be around 250whp @ 14psi if you get your setup car to run right. Post the dyno chart if you can.

[Jadesr20det]

Yea def I will try and post my dyno chart ASAP. I figured that I wouldn't have to mess with the NEO if I just upped the boost becuz I've never heard of neone doing that b4. I'm still using the SOHC MAF. And yea since my boost is so low I believe my wastgate actuator is on its last legs. And yea I was happy about my #'s on such low boost and since I didn't run it on high boost after the FPR was hooked back up so I might try that again after getting a nismo FPR as u advised. Neone have ne advice while I gather my dyno results? Thanks by the way.

[BEST1TUNING.COM]

Ok stop for a second please. NO nismo FPR unless yours is broken. YES you will absolutely have to make adjustments for more boost. Just because the MAF sensor can read more airflow doesnt mean that the ECU has been prepared to trim fuel or ign based on the readings. If the mapping in the ECU is not prepared for the increase in boost it just uses the last available airflow calculation for everyamount of airflow past that point, it would have the effect of the same tuning at 7 psi as 14 psi. More importantly ign. timing.

The way the ECU calculates fuel and ign is an input voltage from the MAF which is converted to a value in a MAF specific 128 byte table (ie. SR ECU has SR MAF table), the value is put into a formula to calculate a suggested Pulsewidth to equal a 14.7 AFR, this value is then applied to the fuel/ign tables where it looks up the proper amount of fuel to add to 14.7 in order to get the proper AFR for that airflow. If it cannot find the calculated suggested pulsewidth value it simply reverts to the greatest value in the table wich is fine for 7psi but the load scale will need to be modified for a larger value range.

The second thing is if your FPR is disconected, this means that there is no return to release fuel back to the tank and your FP should increase at high vac. If anything this would cause your car to run extreemly rich not lean. Even so, your fpr is closed at full throttle anyway so this shouldt have any effect except for partthrottle opperation wich would be rich NOT lean.

Most importantly your are running an SOHC MAF. THIS is where the problem lies. It does not support enough airflow. Nismo will not solve the problem here.
Modified by BEST1TUNING.COM at 2:01 PM 6/4/2007

[zanilth]

Ok stop for a second please. YES you will absolutely have to make adjustments for more boost. Just because the MAF sensor can read more airflow doesnt mean that the ECU has been prepared to trim fuel or ign based on the readings. If the mapping in the ECU is not prepared for the increase in boost it just uses the last available airflow calculation for everyamount of airflow past that point, it would have the effect of the same tuning at 7 psi as 14 psi. More importantly ign. timing.

The way the ECU calculates fuel and ign is an input voltage from the MAF which is converted to a value in a 128 byte table, the value is put into a formula to calculate a suggested Pulsewidth to equal a 14.7 AFR, this value is then applied to the fuel/ign tables where it looks up the proper amount of fuel to add to 14.7 in order to get the proper AFR for that airflow. If it cannot find the calculated suggested pulsewidth value it simply reverts to the greatest value in the table wich is fine for 7psi but the load scale will need to be modified for a larger value range.

The second thing is if your FPR is disconected, this means that there is no return to release fuel back to the tank and your FP should increase at high vac. If anything this would cause your car to run extreemly rich not lean. Even so, your fpr is closed at full throttle anyway so this shouldt have any effect except for partthrottle opperation wich would be rich NOT lean.

Most importantly your are running an SOHC MAF. THIS is where the problem lies. This needs to be accomodated for.

Ok, so if you had a virtually stock sr20 setup, you wouldn't recommend upping the boost any because the ecu couldn't keep up with it? Would the FMIC and exhaust change the readings that much?

[BEST1TUNING.COM]

I would recommend proper tuning at any boost increase because thats how you acheive the best power and reliability. There may be the deception that it is ok to increase boost on the SR but this is only because they are highly detuned from the factory wich leaves room for such modification as an increase in boost etc.

The FMIC is going to help bring cooler denser air into the engine, denser air is higher in oxygen and will cause a change in AFR depending on how drasticaly it has effected the temperature. It will also slightly effect the spoolup time. These modifications however will not effect the AFR enough to read 18:1, this problem lies in his MAF.

As for your question though. No I would not recommend a boost increase with out proper fuel/ign tuning.

[zanilth]

I would recommend proper tuning at any boost increase because thats how you acheive the best power and reliability. There may be the deception that it is ok to increase boost on the SR but this is only because they are highly detuned from the factory wich leaves room for such modification as an increase in boost etc.

The FMIC is going to help bring cooler denser air into the engine, denser air is higher in oxygen and will cause a change in AFR depending on how drasticaly it has effected the temperature. It will also slightly effect the spoolup time. These modifications however will not effect the AFR enough to read 18:1, this problem lies in his MAF.

As for your question though. No I would not recommend a boost increase with out proper fuel/ign tuning.

Alright, well can you recommend something for me then? Aside from fuel pump, and a fmic, with a stock setup what could I use to monitor and make slight tune adjustments? I am definitely not going to spend a couple hundred bucks to get it tuned, then another hundred plus each time I modify slightly.

[BEST1TUNING.COM]

If you really dont want to spend any money on a tune then the only thing I can recommend is getting another MAF. You could get an ECU tune scaled for more boost and a wideband, then fine tune yourself with the AFC. Atleast that way you will have proper ign timing and fuel that is close enough to just clean up with the AFC.

[Jadesr20det]

Wow thanx for the wealth of advice. So I guess ill be in the market for a 300zx tt maf or q45 shortly

[zanilth]

If you really dont want to spend any money on a tune then the only thing I can recommend is getting another MAF. You could get an ECU tune scaled for more boost and a wideband, then fine tune yourself with the AFC. Atleast that way you will have proper ign timing and fuel that is close enough to just clean up with the AFC.

Yeah, its not that I don't want to spend money on tuning...but when I start my project it is going to take a while....step by step, and will probably take a year or two to get where I want. I am not going to pay to have it retuned every time I do something to it. I might just get a biki or something like that, where I can do it myself....Just gotta figure out exactly how. Oh well, thats why I am on here, trying to figure everything out before I start.

[TchouikoS13]

So just outta the blue... what would you recommend to someone with the setup above that wants to beef up the boost w/o rescaling the ecu, yet want to fine tune w/o messing up the ign. timing?

[Jadesr20det]

That's a good question. I think this topic is constantly overlooked or never covered due to the fact that u just hear of guys/girls just turning up the boost on sr's and letting er rip. I myself did this and only knew I was running dangerously lean due to putting my car on the dyno and seeing it 4 myself. Know my next question that I might have the answer to already is, while I had the car at 16lbs. (Not intentionally) why didn't I hear any strange sounds feelings etc? I mean the car was pulling hard (for what it was) and after I'd get to about 50mph I'd let off (so maybe that's the reason). Also due to the fact that we have SR's we cannot tune our ecus for a specific boost setting (correct? If I'm wrong please lmk) when I go to send in my ecu to JWT I just put the setup I have? Ex; 300zx maf, 272 jun cams, 550 injectors etc? And then how do they determine what boost is safe from there for a base. Srry for the long post again but I figure the more myself and others know the happier our motors will be

[BEST1TUNING.COM]

You actually can tune the ECU for a specific boost setting if you know the TP or airflow loadscale value that the ECU uses for that specific airflow.

TchouikoS13:There really is not much I can suggest, and what I could suggest I would rather not because I dont want to come of sounding like its ok to do. To tune for more boost you must have control of ign timing and fuel, as long as you can find something to control both then you are in the clear.

Jadesr20det:Like I said above, it is possible to tune for your specific boost. Its just a matter of finding the correct values. Mail order tunes are somewhat difficult. When I put my tunes together I first ask for MAF, injectors and boost. This lets me get all the proper values inserted in to the ROM and scale accordingly. I then ask for things such as Turbo, cams, head work etc so that I can get a rough idea of the powerband of the car and where its going to most likely be at peak VE, breathe the best and make its torque which, with some experience, allows me to dial in timing better. I also look at dyno charts of very similar or same setups.

Maybe ask JWT what their procedure is as theres might be different.

[TchouikoS13]

Alrighty then. So what can control ign timing (1) and fuel (2)? Well i know you can get a safc and use that, but i was told when trying to lean or rich it out with that, it messes with the timing... which is bad and can effect performance.

Correct me if im wrong.

TchouikoS13:There really is not much I can suggest, and what I could suggest I would rather not because I dont want to come of sounding like its ok to do.

If you'd tell me that would be much appreciated.

[zanilth]

Alrighty then. So what can control ign timing (1) and fuel (2)? Well i know you can get a safc and use that, but i was told when trying to lean or rich it out with that, it messes with the timing... which is bad and can effect performance.

Correct me if im wrong.

If you'd tell me that would be much appreciated.

Lol, he is a business man. He tells you, he doesn't make money.

I believe that if you do some serious mods, you should get a really good tune, by a professional. However, if you are upping the boost with the same turbo, or making minor changes over a period of time, something like a biki would be ideal. Not to mention that by the time you are done, then you will (or should) have the knowledge of everything that has gone on in your vehicle, and can have tested what works and doesn't, for a more overall knowledge of what you are driving.

[BEST1TUNING.COM]

Any thing else is jsut really inefficient. An ECU tune or propper EMS is what needs to be done. AFC should only be for light adjustment.

I dont mind giving advise and I give non biased honest advise regardless of what I sell, to help educate people.

If you do plan on making small adjsutments over a period of time, something like the biki would be ideal, thats why im trying to finish up testing on our usb updatable boards.

[Jadesr20det]

ok so do you tune ecus? i'd rather send it off to a member of the boards and support you if you do. how much would u charge to tune my ecu gt2871r .64, 272 cams, z32 maf, 740cc injectors, and 12 lbs of boost? lmk as im looking to do this shortly.

[BEST1TUNING.COM]

Well I appreciate that very much. I assure you will be happy with this tune since I have just completed one on a very similar setup. The tune w/rescale is $310 plus shipping. Adjustments on the original tune are free.

[zanilth]

ok so do you tune ecus? i'd rather send it off to a member of the boards and support you if you do. how much would u charge to tune my ecu gt2871r .64, 272 cams, z32 maf, 740cc injectors, and 12 lbs of boost? lmk as im looking to do this shortly.

Just out of curiosity, how much hp are you looking to make with that setup and boost?

[BEST1TUNING.COM]

He will be making around 300hp. I have done a few of these.

[Jadesr20det]

well i was looking more towards 350hp as that is what i want until i start working on my spare block. maybe best1 u can advise me on what else would be needed to attain the 350hp mark. 350 is more than enuff for me on a streert driven dd.

[BEST1TUNING.COM]

a little more boost you will be right there. We run 20psi on this one and it is an animal. You will need 18-20 psi. But I can make you a map that will be tuned all the way to 20 psi and also anything below so you can run whatever you would like.

[Jadesr20det]

thanks can you email your info to [email protected].

[BEST1TUNING.COM]

sent but it came back failure. I tried again

[Jadesr20det]

its supposed to go straight to my sidekick. well just email [email protected] then that one always works

[BEST1TUNING.COM]

sent