GD DYNO RESULTS: 2004 STi Built Block, JDM heads, APS FMIC, AMR T60, HKS Exhaust etc etc

[brooksjdmwrx]

i maxed my maf out too on my bpt 20gxtr bb w/ 10cm hotside.. but i tried to buy an aps 65 or 70.. but they dont sell to the US anymore.. im thinkin about the perrin big maf? or the perrin "blow thru boost tube"

 

[Spamby]

20g maxing the maf? Is that possible?

 

[brooksjdmwrx]

my tuner does a great job with gettin power and torque, at the same time as not trying to blow stuff up nor, pushing the limitations on the car/motor etc.. he said it was reading at 300 g/s, and it wasnt the fuel, bc i have bigger injectors(750-850cc* cant rem, lol) and 255lph pump.. but im reading into this 4bar map sensor now. its hellalot cheaper than buying the turbo inlet and short big maf intake.. i was maxing it out around 18psi, but im shooting for 22-27psi on my tune though

 

[brooksjdmwrx]

You need an IAT sensor with the 4BAR. 300g/s is the old max before the new COBB SD mapping. Even then, the injector scaling and maf scaling can be tweaked some to raise the actual air flow if that is the issue. If you're going to shoot for 25 PSI or higher, get an OMNI 4BAR. Speed density is a cheap swap parts wise, but the tune will take considerably longer, even if your tuner is experienced. Tuning a MAF only deals with a voltage of a sensor and making sure the air flow calculation allows for proper fueling. When you get into speed density, it becomes air flow versus pressure versus rpm, making a 3D table with much more data. Even on 16BIT ECUs, SD is a very viable option, and if you're running open source there is a ROM hack that emulates the group N rom and looks very similar to a standalone ECU. Very nice stuff if you get the bugs worked out. So, no matter what tuning option you are using, Speed Density is well worth the effort. If you only have 750cc injectors, those should actually max out quite easily on a 20G if the AFRs are on the conservative side. Local car I drove while it was tuned maxed the injectors at only 20 psi peak tapering to 19 PSI by redline. If you're really shooting for 24 PSI or so with that 20G, double check your fuel system's ability to meet the demands. It's better to have some headroom. You'll see some people talk about "atomization of the fuel" being an issue with larger injectors. I was able to get 30MPG in my car (self tuned) with ID1000cc injectors on a road trip to florida. Good luck bud.

not sure if i did that right... but dude that is freaking awesome info!!! im bout to create a thread in the ecu management area.. can u copy and repaste this for me?

 

[brooksjdmwrx]

sryy to steal ur post/thread build thing... im sorta still new to igotasti,, but ur build is very impressive!! i want to do a full twin scroll set up on my v.7 bugeye when i get done with this hybrid 2.0/2.5 build on my 05'

 

[STIMULA8]

Or just go speed density. All you need is an IAT sensor after the intercooler and a competent tuner. Most times it's an issue of the injectors being maxed out and an incompetent tuner behind the laptop using the MAF as an excuse when in actuality, the car is out of fuel.

I agree with fuji. Find a tuner to go speed density. MY IDC was maxed out with the 850cc's ALSO the MAF voltage was maxed. so, if i want to get protuned again with the APV2 i would get fuel injector clinic's new 1770cc injector thats about to release in the market soon, and instead of pump 93, i would get e85 and speed density.

i maxed my maf out too on my bpt 20gxtr bb w/ 10cm hotside.. but i tried to buy an aps 65 or 70.. but they dont sell to the US anymore.. im thinkin about the perrin big maf? or the perrin "blow thru boost tube"

either one works, i heard the blow thru tube has its qualities, but also some cons. or you could go the speed density route.

You need an IAT sensor with the 4BAR. 300g/s is the old max before the new COBB SD mapping. Even then, the injector scaling and maf scaling can be tweaked some to raise the actual air flow if that is the issue. If you're going to shoot for 25 PSI or higher, get an OMNI 4BAR. Speed density is a cheap swap parts wise, but the tune will take considerably longer, even if your tuner is experienced. Tuning a MAF only deals with a voltage of a sensor and making sure the air flow calculation allows for proper fueling. When you get into speed density, it becomes air flow versus pressure versus rpm, making a 3D table with much more data. Even on 16BIT ECUs, SD is a very viable option, and if you're running open source there is a ROM hack that emulates the group N rom and looks very similar to a standalone ECU. Very nice stuff if you get the bugs worked out. So, no matter what tuning option you are using, Speed Density is well worth the effort. If you only have 750cc injectors, those should actually max out quite easily on a 20G if the AFRs are on the conservative side. Local car I drove while it was tuned maxed the injectors at only 20 psi peak tapering to 19 PSI by redline. If you're really shooting for 24 PSI or so with that 20G, double check your fuel system's ability to meet the demands. It's better to have some headroom. You'll see some people talk about "atomization of the fuel" being an issue with larger injectors. I was able to get 30MPG in my car (self tuned) with ID1000cc injectors on a road trip to florida. Good luck bud.

great response. made everything crystal clear

 

[STIMULA8]

Since I derailed this thread, here's a question for the OP:

Were the JDM heads port matched to the larger bore? If not, you have significantly higher compression. Not necessarily a bad thing, but it's something for people to note when it comes to the power made.

yep theyre JDM V7 2.0 big port heads PnP radius valve and decked, the EJ257 shortblocks bore is 99.75mm, not much over stock. and the block halves to complete the longblock are from a 2011 sti. i guess you can say i have a super hybrid? lmao

sryy to steal ur post/thread build thing... im sorta still new to igotasti,, but ur build is very impressive!! i want to do a full twin scroll set up on my v.7 bugeye when i get done with this hybrid 2.0/2.5 build on my 05'

lol its cool man, youll understand the threads soon. and thanks! good luck with your build! make a thread if you have a dyno graph and post your mods. love to see!

 

[STIMULA8]

Blow thru maf is something I recommend against to be honest.

i originally said -> either one works, i heard the blow thru tube has its qualities, but also some cons. or you could go the speed density route. meaning the bigger maf or the blow thru maf would work, but they have their differences and separate qualities/cons to each.

 

[STi FR3AK]

I'm a little confused as to why you would want the blow thru. If you did go SD, just get a MAF cover.

 

[STIrocks]

YzVpH

 

[STIMULA8]

hahaha ^

 

[HolyCrapItsFast]

Blow thru maf is something I recommend against to be honest.

+1... In just about every case. :tup:

You don't need a Maf cover for SD, that's wasting money and reducing functionality of the system. You can run a hybrid mode that switches from MAF to SD. This way you retain lots of resolution in both putting around town and at WOT.

+1000.

I'm a big fan of hybrid mode. I have used this strategy with great success. The only thing I found is that moving the temp sensor skews the MAF scaling a bit in one direction but it doesn't really matter much because it seems to be the same amount across the board, so it is a delta error. You just rescale it to the new temp sensor location and be done.

 

[STIMULA8]

:hijacked: Warning the thread has been hijacked. haha Keep the Blow Thru VS Speed Density questions off, because I dont have a blow thru maf or speed density tune, start a thread about that and discuss. :justkiddin: and start threading about the dyno plot/mods i posted, AFR, IDC's etc. etc. carry on now

 

[STIMULA8]

break in tune
EJ257 block with drop in Manley pistons. same previous mods. 361/314

 

[yamahaSHO]

+1... In just about every case. :tup:



+1000.

I'm a big fan of hybrid mode. I have used this strategy with great success. The only thing I found is that moving the temp sensor skews the MAF scaling a bit in one direction but it doesn't really matter much because it seems to be the same amount across the board, so it is a delta error. You just rescale it to the new temp sensor location and be done.

The MAF correction vs temperature is opposite of SD temperature corrections. If the MAF temp comp were zero's, it'd run rich when cold and lean when hot (IAT's), where SD would be opposite. That temp comp scaling is there for MAF behavior.

I too like they hybrid setup in making a nice, drivable car all around.

 

[STIMULA8]

I actually was recommended to get tuned to SD by Dave brown, my tuner at PAS. He did, and the car ran so much better

 

[STIMULA8]

delete

 

[Alin]

Nice steady lines! How does the pull feel?

 

[STIMULA8]

I cant explain it! I got my go pro, I need a suction up mount. Dave @ PAS sent me a new map with more boost, Im hitting 1.5-1.6 bar now ~21-22 psi LOL Shes really fun!