Stock 93-95 Prelude Si VTEC injectors?

s300 and SManager software questions & answers
skaterguy1986
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Stock 93-95 Prelude Si VTEC injectors?

Post by skaterguy1986 » Mon Feb 26, 2018 12:59 pm

I've been chasing some odd fueling at idle issues lately and just happened to be poking around on the map that was provided to me and it seems like the injector size is wrong, it's showing as 340cc in my calibration but most of my searching says 310. Wondering how much of a problem that can cause and if changing it to 310cc will require a complete retune. Not sure how far off the dead times are, they seem to match pretty much all the calibrations that are supplied with the software.

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Spunkster
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Re: Stock 93-95 Prelude Si VTEC injectors?

Post by Spunkster » Mon Feb 26, 2018 1:18 pm

Has this been tuned on the dyno with your vehicle?

skaterguy1986
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Re: Stock 93-95 Prelude Si VTEC injectors?

Post by skaterguy1986 » Mon Feb 26, 2018 1:38 pm

Never seen the dyno, been tuning it on the street as best as possible, most of the map is pretty good, it just seems at times the fueling mainly under idle and light load can move around a bit. I may not have a dyno but I have a pretty strong grasp of EFI. Mainly wondering how much of a difference it'll make if I change the box's to the proper 310cc and what problems could be expected to be seen out of a car where the cc was slightly off like mine is. Feels like I'm chasing my tail at times, mainly idle, AFR tends to be pretty inconsistent in open loop when fully warmed up. I've been tuning in open loop only btw, closed loop is disabled since I don't want to fight the wideband.

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Re: Stock 93-95 Prelude Si VTEC injectors?

Post by Spunkster » Mon Feb 26, 2018 1:42 pm

Do you have the correct dead times set for the injectors you are using?

skaterguy1986
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Re: Stock 93-95 Prelude Si VTEC injectors?

Post by skaterguy1986 » Mon Feb 26, 2018 2:01 pm

Hard to say since the chart shown in the smanager doesn't really match the page I found online as far as the voltage increments go so it's hard to compare. If they have similar dead times to the injectors of other OBD1 Honda's then according to all of the base maps supplied with the software they match.

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Re: Stock 93-95 Prelude Si VTEC injectors?

Post by Spunkster » Mon Feb 26, 2018 2:48 pm

What injectors are you using?

skaterguy1986
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Re: Stock 93-95 Prelude Si VTEC injectors?

Post by skaterguy1986 » Mon Feb 26, 2018 3:36 pm

I'm using the stock injectors that came with the JDM H22A engine, it was just something I noticed and there is a lot of conflicting info out there.

crluver123
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Re: Stock 93-95 Prelude Si VTEC injectors?

Post by crluver123 » Mon Feb 26, 2018 7:31 pm

dead times of h22 injectors are not the same as other honda motors.
Set the injector size to 310cc in the map.
Get the car fully warmed up, tune along the way as necessary. Then at idle, make sure ALL electrical things are turned completely off; lights, radio, wipers, heater, everything. Adjust fuel table so it idles steady at about 14.4-14.5. Then unplug the alternator. Go into the fuel injector dead times settings, and raise/lower the dead times for the voltages nearest whatever current battery voltage is until afr is again at 14.4-14.5. Now plug the alternator back in and make sure afr is still steady around 14.4-14.5.

Dead times should be quite spot on now. If fueling continues to bounce around from day to day, then you need to spend more time tweaking the air temp and coolant temp compensations. Also, every time you get gas the characteristics of the gas will be slightly different, especially between different brands of gas. So that will have a pretty big impact on afr, which is why engines have o2 sensors to begin with; to set fuel trims to make up for the inconsistencies in fuel, and weather [humidity]

skaterguy1986
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Re: Stock 93-95 Prelude Si VTEC injectors?

Post by skaterguy1986 » Mon Feb 26, 2018 9:30 pm

As long as you're certain the size is 310cc since I'm searching to find some say 310, 320, 325 and 340. I'm in FL and the weather is kinda wonky this time of year but I had messed with the IAT table some but had no success with that.

crluver123
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Re: Stock 93-95 Prelude Si VTEC injectors?

Post by crluver123 » Mon Feb 26, 2018 9:59 pm

compensation tables can be tricky to dial out.

The only two injector sizes that came in h22 are 290cc and 310cc. And using 310 in the tune should work fine for both

skaterguy1986
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Re: Stock 93-95 Prelude Si VTEC injectors?

Post by skaterguy1986 » Tue Feb 27, 2018 6:35 am

As far as the other voltage values I assume I would just add/subtract the same amount as I did from the values closest to the target voltage and that would probably be close enough?

It's annoying that there isn't really any info or a quick select in the software for these injectors.

skaterguy1986
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Re: Stock 93-95 Prelude Si VTEC injectors?

Post by skaterguy1986 » Wed Apr 18, 2018 6:19 pm

Can the info here be used at all?

http://injector-rehab.com/shop/lag.html

I notice they list them as 330cc, I was playing around with the another tuning software (AEM) to see that they had *stock* OBD1 H22A injectors listed as 330cc as well.

Why the F is there so much conflicting info out there?! I was playing with it today to still get unpredictable fully warmed up idle AFR and crap tip in. Going to try that chart to see where it gets me.

PS: I know, I know, I'm taking forever to play with this but the car lives at my job now (dealer) so I'm more inclined to tinker.

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Re: Stock 93-95 Prelude Si VTEC injectors?

Post by Spunkster » Thu Apr 19, 2018 10:25 am

You will have to try it then fine tune the fuel tables.

G. Wiffington
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Re: Stock 93-95 Prelude Si VTEC injectors?

Post by G. Wiffington » Mon Apr 30, 2018 10:54 am

WOWWWWW excuse me sir but everything that you have been saying is exactly what I have been dealing with for the last few months lol.

I have an H22A Euro R with some 1995 VTEC Prelude Injectors. I bought the injectors off of ebay & they were listed as 93-95 Prelude Si VTEC injectors (345cc).

You are correct about the multiple reports of different injector sizes. I have a 1993 Accord & on the forum for CB7's everyone says these injectors are 345cc. But, I found a page from a forum where someone was saying that for injector cc it really depends on the fuel pressure you are running to really determine what the flow rate is. I think the only way to really figure out is to have a set of these injectors sent to a tester so they can accurately measure the size at the recommended Fuel Pressure.

I found that exact same page concerning injector dead times & I actually went with the 330cc. I plugged them into the Dead Times table in Hondata but for some reason it would not let you do the exact numbers that were listed on that website. Hondata would correct the numbers & cause it to not match what you would input. weird..

I have input 330cc & entered those dead times from the website you provided (even though Hondata auto corrects the numbers). I think it improved my drivability compared to when I had mine listed as 345cc.

So I have been fine tuning the fuel table just as Spunkster said.

Definitely give reports back about what you end up doing or what results are. I am very curious since we seem to be in the same boat!

skaterguy1986
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Re: Stock 93-95 Prelude Si VTEC injectors?

Post by skaterguy1986 » Sun May 20, 2018 4:06 pm

I started to redo it some using 310cc as the setting, that site does say 330cc but you have to remember that they test at 3bar or around 43.5psi. So to be certain between the 2 I'm going to do a fuel pressure test with the regulator disconnected since the stock spec with regulator disconnected 33-40psi which would mean 310cc is actually closer at that pressure.

As far as the dead times go I tried using those times but they didn't work out very well, I ended up doing the dead times manually as outlined in the post above by disconnecting the alternator/adding loads to get the dead times good so that the AFR doesn't alter when the fans cycle or turning on lights, A/C, etc.

To anyone at Hondata (Spunkster/Hondata) since I have a map that was mostly tuned on 345cc as the injector size could I just leave that in the stock size field under the fuel injectors tab and then set the current size to 310cc and let it compensate? Or should I just set both fields to 310cc and retune the entire map?

G. Wiffington, I'm not running the Euro R engine btw, just an OBD1 H22A but using the Euro R manifold modified by Rosko racing with a PLM header which seems to be a popular combo but no base map out there for that.

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