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EVOla_VIRUS
01-17-2006, 04:14 PM
Can someone tell me the difference 680cc vs 720cc injectors will do in giving me back timing in the 3000 - 4300rpm bandwidth? Tuning is done with AFC. I can imagine the 720cc's will allow more advance due to less enrichment but where the AFC points will land me in the timing map in the upper rpm's also peak my curiosity.

Oh..in the search..ive only found "720 are better cause of xyz"...any logging out there? Thxs

Hiro
01-17-2006, 04:31 PM
The difference between 680 and 720cc injectors is 40cc of volume.

Depending on your current tune/parts set up, added fuel may provide a safe condition for your timing to increase steadily through the band stated above. Keep in mind though, that your timing will decrease until your boost peaks (stock turbo: 3500RPM).

The SAFC and lager injectors do not directly control timing. They just "affect" it by providing a stable AFR where by the ECU will advance your timing curve. You may find you can run just as much timing with 680s as with 720s (again depending on what mods you have).

Hiro

EVOla_VIRUS
01-17-2006, 04:38 PM
The difference between 680 and 720cc injectors is 40cc of volume.


Hiro


I can subract :2funny:

Using 720's will require less enrichement I believe...and the signal intercept will return higher ignition advance
Using 680 will require more enrichment than 720's I believe....and the signal intercept will return lower ignition advance vs 720's

Seems like where the peak torque occurs, enrichment is needed and from that enrichment, my timing goes down.

rsmatt
01-17-2006, 04:46 PM
720s are counter productive on 91 octain and a stock 16g. the reason being with the 720's you will pull so much out ( referance to the neg cor value on the afc ) on the afc that the ecu will try to throw to much timing and knock just enough to throw the timing back. now on the other hand if you are going to run 100+ octain, meth injection, or a bigger turbo the 720's are the injector to go with.

basicly the 680's are going to be more forgiving to tune on a stock turbo car.

evo8kiko
01-18-2006, 05:52 PM
The difference between 680 and 720cc injectors is 40cc of volume.

Depending on your current tune/parts set up, added fuel may provide a safe condition for your timing to increase steadily through the band stated above.* Keep in mind though, that your timing will decrease until your boost peaks (stock turbo:* 3500RPM).

The SAFC and lager injectors do not directly control timing.* They just "affect" it by providing a stable AFR where by the ECU will advance your timing curve.* You may find you can run just as much timing with 680s as with 720s (again depending on what mods you have).

Hiro

720cc are OVERKILL unless you are gonna run like a GT35Turbo and well over 27psi. But if you are just gonna tune for pump save your motor and just run 20psi. Even up to 24psi you can still get away with the Stock injectors with some tuning and Racefuel.

HEre's a couple of 3rd gear Pulls if you dont mind....

1st log at 3rd gear pulls 19 psi w/ walbro 255
RPM Timing O2 1 Bank 1
2863 41 0.02
3027 43 0.88
2957 29 0.86
2984 24 0.86
3039 21 0.88
3125 18 0.9
3215 16 0.92
3301 12 0.92
3410 9 0.92
3512 8 0.92
3633 6 0.92
3750 4 0.94
3883 7 0.94
4020 8 0.92
4168 7 0.92
4297 7 0.94
4426 8 0.94
4547 8 0.94
4684 6 0.94
4801 7 0.94
4941 7 0.94
5070 8 0.94
5199 6 0.94
5293 6 0.94
5391 5 0.94
5484 5 0.94
5590 6 0.96
5695 7 0.96
5809 8 0.96
5902 9 0.96
6000 10 0.96
6113 10 0.96
6207 11 0.96
6320 12 0.96
6410 12 0.96
6504 14 0.96
6598 14 0.96
6684 15 0.96
6770 15 0.96
6867 16 0.96
6930 18 0.96
7008 18 0.96
7090 18 0.98
7156 18 0.98
7227 18 0.98
7309 18 0.98
7375 19 0.98

Here the SEcond Log w/ 10 min Brake in between pulls.
RPM Timing O2 1 Bank 1
2980 9 0.92
3082 7 0.92
3188 6 0.92
3305 4 0.92
3422 2 0.92
3547 2 0.94
3668 4 0.94
3805 6 0.94
3934 7 0.94
4063 7 0.94
4172 6 0.94
4320 5 0.94
4438 6 0.94
4555 7 0.94
4680 6 0.94
4820 6 0.94
4934 7 0.94
5047 8 0.94
5176 8 0.94
5285 8 0.96
5422 8 0.96
5516 8 0.96
5625 8 0.96
5746 10 0.96
5879 10 0.96
5953 12 0.96
6082 13 0.96
6188 12 0.96
6281 14 0.96
6359 15 0.96
6465 13 0.96
6551 13 0.96
6633 13 0.96
6715 14 0.96
6801 15 0.96
6895 16 0.98
6977 16 0.98
7063 18 0.98
7137 17 0.98
7203 18 0.98
7289 18 0.98
7324 19 0.98

These are Stock injectors on 91 pump. If you look at the timing advance evo's run fat to begin with. Now you want to throw in 720's and make it more rich, and try to correct that with a SAFC, YOu'd be maxing out all the way to the NEG's would probably need to take more fuel out or just run RACE GAS every day. I guess anything higher than 720's you might as well invest in an AEM EMS put your money right there.

leaveit2bevo
01-19-2006, 07:33 PM
you guys saying the 720s are to big and dont work on 91 on stock turbo evos are on crack like 90% of the evos I know with this setup have the 720s my timing is perfect and I make a lot of power.

Blaze
01-19-2006, 07:37 PM
you guys saying the 720s are to big and dont work on 91 on stock turbo evos are on crack like 90% of the evos I know with this setup have the 720s my timing is perfect and I make a lot of power.


I knew a guy who ran 720s and hydro-locked his engine!

Blaze
01-19-2006, 07:38 PM
I knew a guy who ran 720s and hydro-locked his engine!


Yeah, I'm full of sh&7.

superman105
01-22-2006, 11:59 PM
do I add some fuel to get rid of knock ?



base on your second log, you have about 3 degree my timming being "Knocking", you are still running pretty rich, lean it ou more. the number steady climb up, if you it drop and climb back up, that mean it's knocking. form 2000-3400rpm looks good, 3500 and up are a bit rich, lean it out about 2% on the SAFC and see what happens. anyway the one that are highlighted red show you it's knocking.O0

2980* *9* *0.92
3082* *7* *0.92
3188* *6* *0.92
3305* *4* *0.92
3422* *2* *0.92
3547* *2* *0.94
3668* *4* *0.94
3805* *6* *0.94
3934* *7* *0.94
4063* *7* *0.94
4172* *6* *0.94
4320* *5* *0.94
4438* *6* *0.94
4555* *7* *0.94
4680* *6* *0.94
4820* *6* *0.94
4934* *7* *0.94
5047* *8* *0.94

Blaze
01-23-2006, 09:10 AM
You just posted someone elses chart and asked if you need to remove fuel from your fuel map to reduce your knock?

While I'm tempted to delete this post, it's probably better that the question is answered and the following stated:

Answer: On 91 octane the target voltate should be around .91 to .92 from 3500-6000. From 6K on, you can run between .92 and .93. A consistant .91 to redline is certainly possible, but it often means you're running on the lean side in you top end. Probably good for the 1/4 mile or light to light runs. But not so hot for long durations/ie track cars.

If you find a log at or below .91 and you're loosing timing, you should add fuel to correct it. If you @ .94 or above, it's will likely help to reduce your fuel.

1. Never guess with your fuel curve. Use a pocket logger and/or wide band when tuning your car. Never tune with an EGT by itself or the famous butt dyno.
2. Never use someone elses settings on your car. All cars (even stock/stock) are going to be different.
3. If you don't know something, ask. Tuning isn't hard. Learning to tune isn't hard. But you need to understand fully what you're doing before you damage a car.



do I add some fuel to get rid of knock ?



base on your second log, you have about 3 degree my timming being "Knocking", you are still running pretty rich, lean it ou more. the number steady climb up, if you it drop and climb back up, that mean it's knocking. form 2000-3400rpm looks good, 3500 and up are a bit rich, lean it out about 2% on the SAFC and see what happens. anyway the one that are highlighted red show you it's knocking.O0

2980 9 0.92
3082 7 0.92
3188 6 0.92
3305 4 0.92
3422 2 0.92
3547 2 0.94
3668 4 0.94
3805 6 0.94
3934 7 0.94
4063 7 0.94
4172 6 0.94
4320 5 0.94
4438 6 0.94
4555 7 0.94
4680 6 0.94
4820 6 0.94
4934 7 0.94
5047 8 0.94

earlyapex
01-26-2006, 04:28 PM
Answer:* On 91 octane the target voltate should be around .91 to .92 from 3500-6000.* From 6K on, you can run between .92 and .93.*

1.* Never guess with your fuel curve.* Use a pocket logger and/or wide band when tuning your car.* Never tune with an EGT by itself or the famous butt dyno.

You say never guess with your fuel curve but you tell him the target narrowband voltage should be .91 to .92.

A. Narrowband is way too inaccurate to tune to the edge.
B. .91 to .92 is leaner than you think. My wideband shows 11.8 (on 100 octane) yet my narrowband is anywhere from .92 to .94. My wideband on 91 shows 11.1 to 11.4 yet the narrowband is anywhere from .94 to .96.

What do you think .91 would be on 91 octane. Of course every car is different on narrowband, which again is another reason not to trust them. .91 might work for your car but not for others and vice versa.

Blaze
01-26-2006, 04:38 PM
You say never guess with your fuel curve but you tell him the target narrowband voltage should be .91 to .92.

A. Narrowband is way too inaccurate to tune to the edge.
B. .91 to .92 is leaner than you think. My wideband shows 11.8 (on 100 octane) yet my narrowband is anywhere from .92 to .94. My wideband on 91 shows 11.1 to 11.4 yet the narrowband is anywhere from .94 to .96.


Agreed.
But I also stand by what I stated.

.91-.93 readings have proven consistantly to have stable AFR ratings.
My wideband has found them to be between 10.8 and 11.2.

Not everyone can afford a nice wide band logger.
That could be an argument for "not everyone can afford to tune".

For those who can't afford it and wish to tune with just a logger, those values are sound. And I don't mean to speak from my experience alone. There are multiple threads on this here an on www.EvoTuners.net

Blaze

earlyapex
01-26-2006, 04:42 PM
For those who can't afford it and wish to tune with just a logger, those values are sound.* And I don't mean to speak from my experience alone.* There are multiple threads on this here an on www.EvoTuners.net

Blaze


Can I agree to disagree? hhehe.

I still think tuning to the edge with a narrowband is asking for trouble but if people want to take that risk then by all means go for it.

Blaze
01-26-2006, 04:44 PM
Can I agree to disagree? hhehe.

I still think tuning to the edge with a narrowband is asking for trouble but if people want to take that risk then by all means go for it.


That, my friend...should be a sticky somewhere....

turbolarry
01-27-2006, 01:58 AM
I still think tuning to the edge with a narrowband is asking for trouble but if people want to take that risk then by all means go for it.


Tuning with only a narrowband is probably asking for trouble, but that's why you use it in conjuction with knock/timing, and EGT's. You need as much information as you can get about what's going on in the cylinders to really tune a car.
I would also love to see some peoples timing (or lack of) who are using the S-AFC with just a wideband AFR.

Hiro
01-27-2006, 11:06 AM
I would also love to see some peoples timing (or lack of) who are using the S-AFC with just a wideband AFR.


A few come to mind already.... :roll:

LaminarFlow
02-20-2006, 11:09 PM
When you guys talk about "tuning to the edge"... I'm trying to understand what the edge represents..

My guess, adjust the AF ratio at each rpm setting to the first sign of knock, then back off slightly. Only the pocketlogger can accuratly show when knock occurs, right? So the Wideband tells you exactly what the AF ratio is at. A percent change is detectable with a WB, but probebly not with the pocketlogger. So you gotta use both to fine tune. Am I on the right track?

Bty, I'm about to buy injectors, and am still not clear which is best, 640,680,720. I'm following the dr gray route, and the recipe says 720. I don't ever plan to upgrade my stock turbo. So back to the original post, is there an advantage to 720 or disadvantage to a smaller injector?

Blaze
02-21-2006, 09:40 AM
Tuning to the edge can mean something different from person to person. For me, it represents a max attack tune for either a dyno figure or a 1/4 mile run. That would mean running as lean as possible and keeping an agressive timing curve, all the while avoiding any engine knock. Pushing the edge should never mean sacrificing safety.

Pocket loggers do know show you knock. They show timing. Knock is assumed when at any point your timing decreases. If you want to record knock you'll need a logger that can see it or a stand alone that can monitor it.

Widebands do not necessarily tell you what your AFR is. For example, if you have your wide band mounted on your O2 housing then you're getting a fairly accurate reading. If you have it mounted @ your test pipe...well the figure is going to be slightly off. If you are sampling the AFR after a cat, slightly more and if you clamp a probe to the muffler tip....well you can imagine the difference can be up to 1 AFR point.

What wide bands are excellent for (regardless of their mount point) is establishing a smooth and consistant fuel curve (with emphasis on consistancy). And yes, they are leaps and bounds ahead of the O2 voltage readings of a logger in this respect.

In order to tune, you need to have multiple sources of information. You want to see your AFR, your engine timing, engine knock, temperatures and RPMs. If you have a stand alone, good for you. But if you don't, you may want to invest in some equipment where you can get this information.

Regarding injectors:

660s are generally sufficent for a car w/o a turbo upgrade.
720s are the max size you can tune with a SAFC.
1000s are for stand alones and large turbos

If Scot Gray is doing your tune, you go with the parts Scot Gray suggests. He put together a kit based on experience and practicallity.

(and he is the shizzle)

((not to be confused with the jnizzle))

Knower
02-22-2006, 02:48 AM
The ability to log knock directly doesn't mean that you can't accurately infer the occurence of knock based on timing. You know your airflow so you know which timing table you're on and can do some simple math to see how many degrees of timing have been pulled due to knock. It's not the most direct way, but it's not inaccurate.

Blaze
02-22-2006, 08:46 AM
The ability to log knock directly doesn't mean that you can't accurately infer the occurence of knock based on timing. You know your airflow so you know which timing table you're on and can do some simple math to see how many degrees of timing have been pulled due to knock. It's not the most direct way, but it's not inaccurate.


I think I said that, but yes, you're 100% correct. And if you don't have a gazzillion dollar logger that reads knock, a logger that can track the course of your timing curve is definately your next best bet.

But also consider the fact that knock may occur prior to your engine pulling timing. For example, you may start to get 2-3 counts of knock @ 4600 where the car limits timing. Then @ 5400, you get enough knock that the engine pulls timing back.

The actual point you need to address the issue is back at 4600, but using a pocket logger, you might guess closer to 5-5500 to make an adjustment.

It's an exaggerated example. But it's something to keep in mind when using a pocket logger to tune.

Blaze

EVOMANIAC
02-22-2006, 09:24 AM
I dont have a log available, but when my car was tuned we had timing pulled to 5 deg and advanced smoothly up to 21 deg. This is with 720's and Walbro 255, TBE, intake, and stock turbo and cams. My AFR is around 10.6-10.8. Not the best, but safe. Why did I buy such big injectors? Future upgrades. I dont want to spend the money on two sets of injectors. As for knock we used headphones through my WB/logger. Got 3 ticks at one point, but timing kept advancing smooth.

trinydex
04-29-2006, 10:38 PM
headphones?

C-Spec
04-29-2006, 10:50 PM
if you are good and pay attention closely you can feel it. O0

earlyapex
04-29-2006, 11:53 PM
headphones?


yup, "det cans" hooked up to the block. You can hear the ping.

http://autospeed.drive.com.au/cms/A_0353/article.html


use the force luke...

GokuSSJ4
04-29-2006, 11:56 PM
headphones?


yup, "det cans" hooked up to the block. You can hear the ping.

http://autospeed.drive.com.au/cms/A_0353/article.html


use the force luke...

bah! :grin:

trinydex
04-30-2006, 12:18 AM
i've never heard knock or det before :\, maybe a good thing? or a really bad thing :\. does it really sound like tink tink?