DYno Result

[DAT240Z]

I went to the dyno yesterday and I'm a bit disappointed in the result as i was hopin for 230-250- rwhp . my first run was at the stock setting psi and got 190 wrhp, AF was very good so i took it up to 10pis and got 198wrhp and AF mixture still but when i tried to go 12 psi it started to ping and the guy had to back off, then i was like try 15 psi,( 15psi is where i would like to run) so he get on it and if start to ping so he get off again this time we make 215 wrhp but only got the RPM up to 5500. I had them stop and left on the way I had the boost set at 12psi I tried to run at 12 psi and it ping so I pulled over to check things out and found that the distributor was advanced as fas is it could go so I turned it back half between full retard and adv. got back in the car and now I can boost 12psi all day. I want to go back to the dyno and see if this makes a difference but before I go I would like to know what you guys think could this have been my problem, the guy at the dyno shop told me I need more fuel as I ran lean on the last two runs, I just wonder if my lean condition was caused my timing being so far advanced.

 

 

 

MY set up

 

71 240z

83 turbo set stock management system

89 supra intercooler

turbo x blowoff valve

manual boost controller

LSD

3" EXT. part press bend and part mandrel

3" muffler

custom 2 "1/2 down pipe from Scottie g

cold air intake

plug stock pop valve opening

93 octane gas[/img]

[Guest bastaad525]

Wow... a bit lower than I would expect, given I made very similiar power with less mods (bone stock everything, 2.5" press bent exhaust, stock DP, no I/C) at 10psi.

 

Very interesting...

 

But, there is hope Well, first thing I can say is, you NEED more fuel, and you are taking a BIG risk with your engine running 12psi like that until you get it. Stock, the ZX EFI, even at 9-10psi, will run nice and rich up to about 5k rpm, then will start to lean out dramatically (and dangerously). Even with an I/C, you probably should not be running 12psi w/o some way of getting some extra fuel in there, either by way of an adjustable fuel pressure regulator, or bigger injectors, as the stock EFI just isn't able to compensate for the extreme increase in airflow by itself. You will most likely also need to upgrade the pump as the stock pump will be getting very close to the limits of it's abilities by this point, though my own experience showed that the pump was enough to supply my 200rwhp @ 10psi, as when I upgraded my pump to an MSD high flowing pump and went back to the dyno it made NO difference whatsoever in my power or A/F curve.

 

Retarding the timing may help you to avoid detonation running 12psi like that, but it's a risky biz, and I am guessing you are LOSING more power by retarding the timing than you are by running the higher boost. Yo2001, another member here, saw DRAMATIC differences in hp and torque from small changes in timing, and it sounds like you retarded yours a lot. My car is very sensitive to even small timing changes, with very noticeable differences in power and driveability especially OFF the boost. Check your timing with a timing light and set it to stock (24* BTDC in your case) or a couple degrees retarded, maybe 20-22*. I doubt adjusting the timing one way or the other would affect your A/F ratio much, so chances are you are still running WAY lean. I would turn the boost back down to 9-10psi for now and get an adjustable FPR and fuel gauge and turn your fuel pressure up to like maybe 40psi. You can pick up the MSD adj. FPR (MSD part #2222, with a boost/vacuum reference) from overboost.com for about $60, and make your own fuel pressure gauge setup from Home Depot for about $10-15 (just some brass parts to make a tee and the guage itself, which is actually a water pressure gauge for sprinkler systems but works fine for fuel, me and a couple other guys use them). Less than $100 right there and you're lean problem should be solved. Or you can get larger injectors, which will probably cost you a bit more but there are some injectors that you can pick up cheap from the junkyard or whatever that will work fine. Then you can pop open your airflow meter and adjust it to lean out the idle-low-mid RPM ranges to compensate for the extra fuel while still maintaining the extra fuel on the top end (the stock AFM doesn't seem to affect the A/F ratio at WOT after about 4-5krpm, so you can easily lean it out like that in the low-mid ranges like that while fuel pressure alone would dictate your A/F ratio).

 

I'm willing to bet that you would see a noticeable power gain by simply getting more fuel in there to keep from running lean like that. Remember, optimal A/F ratio for a turbo'ed motor is around 12:1, for safety and to get good power... whereas one of your runs (the green line) hits what... 18:1 there for the last 1k rpm!!! You're lucky you were able to drive away from the dyno at all....

 

Only last thing I can think of is you may want to plan on one day swapping out that I/C for a better one. I'm not sure of the one your using but I know the common oppinion is that a lot of the factory stock I/C's are usually too restrictive. Again, I might be wrong on this one and the stock Supra I/C may be fine, but then again, I guarantee you can do better.

 

So turn the boost down for now (I know it hurts bro but you'll be better off in the long run, TRUST me) put your timing where it's supposed to be, and make more fuel your next priority. Then get back to the dyno and tune it.

[DAT240Z]

I have a set of 370ccinjectors that i will be intsalling in the next few days. I'm waiting for my new fuel rail

[Guest bastaad525]

That should give you more than enough fuel. Remember you will have to adjust the AFM spring tension to compensate though or you're gonna run richer ALL the time, and the cars gonna run like crap off the boost. However, as I said at that point the fuel pump may start to max out or be past max, so you probably want to look at that as your next upgrade. Only a trip to the dyno will tell. I'd head to the dyno right after putting those injectors in and get your AFM dialed in then, and if you still see it leaning out on top, you know the fuel pump has gotta go. In the meantime, stay outta the boost or turn it back down... I can't stress that enough dude if you dont want to blow your engine. 18:1 AFR is NOT good, retarded timing or no.

[DAT240Z]

Hi

525 on the afm when i install the injectors do i want to turn thr wheel in the AFM aas to put more tention on it to lean it out or do i go the other way?

I will turn the boost back to 6psi tomorrow before i drive it

[Guest bastaad525]

Well you don't gotta go THAT far!!! Heheh dont suck all the fun out of it. 9psi should be fine. Hell I run 10 with no I/C, but I never rev above 5k or 5500 tops if I'm not 'paying attention'. On the dyno I was running about 13:1 air/fuel above 5k. Odd thing is, even though the I/C helps prevent detonation by cooling the intake charge, it can also encourage it because the colder air is more dense, packing more oxygen, causing you to run leaner and still risking detonation.

 

You wan to tighten the spring tension on the AFM flapper door, which means you want to turn the gear/wheel clockwise. Tightening the door means it will open less for a given amount of airflow, meaning it is seeing less air, and will therefore supply less fuel. However, the door is open to it's maximum by about 4-5k rpm at WOT, at which point the ECU just switches over to a preprogramed curve based on RPM and head temp alone (I may be wrong there may be one or two other factors involved).

 

Dont forget to get a timing gun and moving your timing back to stock... you're probably down a lot on power having retarded it so much.

[DAT240Z]

525 I thought it was posiable to get 250rwhp out of the stock set up, I just don't understand why my set up did not get there

[Guest bastaad525]

well... yeah I kinda know what you mean. When people say "250hp out of a stock setup" they are mostly referring to the limitations of the stock T3 turbo itselt, and the injectors. The stock motor is definately good for it. The stock T3 can get you there, I think, but you'll be pushing it and probably shortening it's lifespan a bit. I dont think i've seen or heard of anyone who actually put down 250hp to the wheels using stock injectors and stock EFI without some kind of mod, at least increasing fuel pressure, and not on the stock fuel pump. BUT I do definately think it's possible with small mods like those. Again, look at my setup. Bone stock pretty much everything, running 10psi with no intercooler, crappy 2.5" press bent exhaust, and starting to run lean after 5000rpm, and I put down 200rwhp. I've seen guys who have gained 20hp or more on stock setups by simply switching to a full, 3" mandrel bent exhaust (I see you mention your exhaust is partially press bent... this DOES make a difference). An I/C would definately be good for more power just by way of a colder intake charge, how much I couldn't say but I guess 5-10hp running the same boost level. With the I/C, I could also safely turn the boost up another few PSI, which should be good for at least another 15hp as well. Add those up and the potential for my setup, once/if I should ever get around to doing those mods, is pretty close to 250 at the wheels. Since you've already done most of that you should already be there as well, assuming everything were running right. However, we BOTH need more fuel for any of those mods to really help at this point.

 

Remember that HP isn't what's measured on a dyno, it's just a multiple of your torque #'s, which is what the dyno really measures. You're torque numbers were really good, where the fuel was there to support it in the lower revs. You were putting down some 30 ft lbs more than I am at about the same RPM, which means you should be putting out a comparable amount of HP more than me as well. So pay attention to that... I think with those torque numbers you're actually much closer to your 250rwhp goal than you think. Your HP number is really just a reflection of how high in the rev range your engine can produce good torque. Your torque falls off FAST as your revs go up, because your motor is running way too lean up there. Get more fuel, your motor will keep that torque up longer, and I think you'll definately see a higher HP number.

 

I'd bet money, get your A/F ratio to about 12:1 all the way up, get your ignition timing right, set your boost at like 12-13psi (15 is gonna tax your turbo a lot) and you'll end up with something like 230-240hp.

[DAT240Z]

525 as soon as I have my new injectors in and timing set i will head back to the dyno and post my result. Y ou have been a big help.

Thanks for you time

[Guest bastaad525]

no problem dude... usually got nothin better to do than think and chat about Z's (but seriously IS there anything better!) well good luck and be sure and let us know after you dyno again, what you put down this time.