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Low-Speed
06-24-2019, 07:43 AM
I hooked up the DRB3 to my car yesterday. To check the tuning as Eric suggested. My Adaptive Fuel #'s were very close to 0 across the board, with 2 exceptions, both of which were in the short term, and both of which showed a change at release of throttle, under 2K RPM's.

The AFR's are mid to high 12's.
Knock retard is 0, and timing is running between 29 and 31 degrees on a S2 in DAB3.

Something we found very interesting, under light load, at higher RPM's (3000) the timing is above 50 degrees!

My boost is currently up to 17/14. I will be cranking it a little more today, (looking for 18-19/15) and checking again with the DRB. So far, I'm extremely happy with the tune!

DJ2
06-24-2019, 12:09 PM
try some "TORCO Accellerator" next time you run in HOM. Between the TORCO and 100% Meth spraying my knock stays @ 0 and my timing is between 19 and 22 at WOT, you can actually feel the power differnce with the timing lower and it is much better for yout engine also.

Low-Speed
06-24-2019, 12:33 PM
try some "TORCO Accellerator" next time you run in HOM. Between the TORCO and 100% Meth spraying my knock stays @ 0 and my timing is between 19 and 22 at WOT, you can actually feel the power differnce with the timing lower and it is much better for yout engine also.

Mine indicates it's doing better than yours with Meth!

HOM increases timing, hence the added power. I'm on pump gas right now. And 30ish seems to be the timing limit for DAB3. HOM tries to up it, and it gets about 4 degrees knock, and kicks me out. Incidentally, 4 is the # that came up on my DTEC under knock when I tried that, and it kicked me out.

I'm able to hold 29+ on 93 octane. I would hope it would add that 4-5 degrees with high octane gas. I'm going to try to up the boost a bit more. I feel confident 18-19/15 would be fine with the setup now!

Which computer/setting do you have that it's only running 22 degrees timing?

Oh, as for accuracy, I don't know. Mine shows +10 difference, Cam to Crank signal on the DRB3, and then holds in that 30 area. We may be talking about the same thing, because of the offset the factory diagnostic equipment shows. But, I don't need meth/octane booster to hold that. We have some rather good, non-oxygenated 93 around here! None of that Cali piss-water 91 you guys have to deal with!

Low-Speed
06-24-2019, 12:38 PM
I'm out to test. I'll let you know when I get there!

BTW, I'm fairly confident I'm over 270 hp now. I'm looking to break 280 without upgrading the exhaust/FMIC. With a little luck, I'll get 290+ with HOM and race fuel! But I have to get a good base tune first!

sota
06-24-2019, 12:46 PM
get an AeroForce ScanGauge bro. you'll love it.

Low-Speed
06-24-2019, 09:39 PM
I'm kinda broke, and I can get the actual Chrysler DRB3 unit to use most weekends. And, it shows everything. Knock Retard, Timing, Inlet Air Temps, Ambient (Battery) Temp, etc......

Not to mention long and short term adaptive fuel numbers for all 23 cells the NGC3 in the car monitors, upstream and downstream o2's, etc.

It's better than the aftermarket for getting data. And cheaper too! (Free to use!)

blackbird
06-25-2019, 06:03 AM
try some "TORCO Accellerator" next time you run in HOM. Between the TORCO and 100% Meth spraying my knock stays @ 0 and my timing is between 19 and 22 at WOT, you can actually feel the power differnce with the timing lower and it is much better for yout engine also.
What was your setup again? If you're on stock turbo with S2 or S2, either one in high octane mode, you should be seeing a lot more timing advance than that unless you're tricking some of the sensors, etc.

blackbird
06-25-2019, 06:19 AM
I hooked up the DRB3 to my car yesterday. To check the tuning as Eric suggested. My Adaptive Fuel #'s were very close to 0 across the board, with 2 exceptions, both of which were in the short term, and both of which showed a change at release of throttle, under 2K RPM's.

The AFR's are mid to high 12's.
Knock retard is 0, and timing is running between 29 and 31 degrees on a S2 in DAB3.

Something we found very interesting, under light load, at higher RPM's (3000) the timing is above 50 degrees!

My boost is currently up to 17/14. I will be cranking it a little more today, (looking for 18-19/15) and checking again with the DRB. So far, I'm extremely happy with the tune!
Sounds likes it's pretty good and that's about normal for timing. The dial-a-boost does not directly have any affect on timing, but indirectly will have an affect by altering the amount of boost run (and therefore what the MAP sensor measures, what the PCM reads, and then subsequently what the PCM calculates is required for coniditions). Under light load and cruising the computer will advance the timing a lot because there is either minimal load and/or minimal or no fuel being burnt and therefore not much risk for knock. What you want to pay attention to is under load and boost with at WOT and also if you have any part-throttle boost building due to whatever boost control setup you're running.

Under WOT pulls if the intake charges are kept in check a stock S2 car should see about 30-32 degrees timing on the top end on pump gas and about 34-36 degrees when on race gas under high-octane mode (the S3 setup runs less than that and S2 has the most aggressive timing curve of all the stock/"Stage" computers). If you are on the stock intercooler in warm weather, have the S2 WGA spring tension turned up a little, only have 91-octane pump premium, and a few other similar factors may cause S2 to run a bit less timing advance.

Your boost is a little down on what some S2 cars run but that can be affected by a lot of things to include climate and starting atmospheric conditions. You might also want to verify the boost gauge reading against the DRB-III. If you bump it up a little more and can keep everything like that you should be good. Only thing that's a little of a concern is the A/F ratio. If that's from a wideband on the car that's getting pretty lean for a stock turbo. Since I (usually) can't keep track of everyone's specific setup can you give a quick run-down (which is good later on if you change the car around and someone references this thread). The more advance the car runs the lower the EGT's, so as long as it's not retarding timing they might be reasonable. But if you crank the boost up you'll also be increasing back-pressure which if combined with a little timing getting pulled might be on the too hot side for some stock components. That's about the only other thing I'd be monitoring if you intend to run it that lean.

Low-Speed
06-25-2019, 07:21 AM
Sounds likes it's pretty good and that's about normal for timing. The dial-a-boost does not directly have any affect on timing, but indirectly will have an affect by altering the amount of boost run (and therefore what the MAP sensor measures, what the PCM reads, and then subsequently what the PCM calculates is required for coniditions). Under light load and cruising the computer will advance the timing a lot because there is either minimal load and/or minimal or no fuel being burnt and therefore not much risk for knock. What you want to pay attention to is under load and boost with at WOT and also if you have any part-throttle boost building due to whatever boost control setup you're running.

Under WOT pulls if the intake charges are kept in check a stock S2 car should see about 30-32 degrees timing on the top end on pump gas and about 34-36 degrees when on race gas under high-octane mode (the S3 setup runs less than that and S2 has the most aggressive timing curve of all the stock/"Stage" computers). If you are on the stock intercooler in warm weather, have the S2 WGA spring tension turned up a little, only have 91-octane pump premium, and a few other similar factors may cause S2 to run a bit less timing advance.

Your boost is a little down on what some S2 cars run but that can be affected by a lot of things to include climate and starting atmospheric conditions. You might also want to verify the boost gauge reading against the DRB-III. If you bump it up a little more and can keep everything like that you should be good. Only thing that's a little of a concern is the A/F ratio. If that's from a wideband on the car that's getting pretty lean for a stock turbo. Since I (usually) can't keep track of everyone's specific setup can you give a quick run-down (which is good later on if you change the car around and someone references this thread). The more advance the car runs the lower the EGT's, so as long as it's not retarding timing they might be reasonable. But if you crank the boost up you'll also be increasing back-pressure which if combined with a little timing getting pulled might be on the too hot side for some stock components. That's about the only other thing I'd be monitoring if you intend to run it that lean.

Basically stock car. Mopar Cat-Back, S2 w/Toys, DTEC FC, AGP WGA.
I'm still upping the boost, but was concerned with going too far because of knock. I am aware of the heat related issues with running that lean, but the power is far better near the optimal power curve for gas of 13.0-13.2. If I cook the manifold, it gives me a reason to go big turbo!

WOT, it was 29-31 degrees, about 90 ambient, 120 was the high for the IAT's, with the sprayer off. At 80 ambient, later in the day, pushing a little more boost, the IAT's were down around 110. Fuel table looks great though. So, I'll stay lean, and risk the heat issues. I was surprised to see it doing that well. I'll have a MBC here later this week, so I can better dial the spike/hold I'm looking for.

blackbird
06-25-2019, 11:49 AM
The maximum safe power on most turbocharged vehicles will be around .80-.85 Lambda. The stoichiometric point of pure gasoline is 14.7:1 which would equate to about 11.75-12.5 gauge AFR (assuming you're using a wideband set up or configured to calculate AFR from the measured stoich Lambda point of pure gas). You can run a little leaner (say up to around .90 Lambda) on naturally aspirated engines for max power and on some less efficient forced induction cars should run a little on the richer side of that range. Our stock turbo would fall under that category. Also if you live in an area that has 5 or 10% oxygenates added to the gasoline that will probably lower the stoich point to around 14:1 and therefore a max 11.2-11.9 AFR using that .80-.85 range.

The leaner you run it you might make a little better power but the risks can be pretty high. I doubt the turbine and manifold would be the first to let go in your car. More than likely it will be stock cast eutectic pistons and more specifically the top ring land getting weakened by excessive EGT's and the occasional knock the engine will still see under normal operation. Now if you get a fast acting thermocouple and EGT gauge and are seeing a max of ~1650-1700 on the hottest cylinder when you're running high boost on the top end of the rpm's with lower to mid-12:1 AFR's then I'd say you're in good shape. But I'd highly doubt you're running that cool on a leaner than 13:1 AFR.

So if you're comfortable with possibly cooking the engine, not just the turbo, then keep pushing it. If that is a concern you might want to dial back those AFR's, install a water injection setup, or preferably get an EGT gauge so you will know if it's safe or not. If you do eventually upgrade to a bigger aftermarket turbo then you might be able to get away running a little leaner since you'll more than likely be running a much bigger exhaust housing and turbine wheel that won't have as much exhaust back-pressure.

Last note is I'm hoping your air/fuel ratio's are out on the street and not from a dyno session. The dyno doesn't load the car as much and most inertia Dynojet-style dynamometer's will read about half a point richer than the car is actually running out on the street for the SRT-4's. Somewhat related to that is if you're doing street tuning and using the DRB-III you'll have a lot of info to work with. But if you plan on dialing it right up to the maximum and don't have a scan gauge installed you won't always know what knock retard is doing. If you drive to different elevation or load, atmospheric conditions change, you get a little worse batch of fuel or any number of other conditions it's easy to push it right over the edge. Running too lean and too hot with a sudden spike of knock is all it takes to kill something.

Stage2BlackSRT4
06-25-2019, 12:13 PM
x2 on the EGT. even with w/i and a very free flowing set up my 50 trim hits 1600+ very fast with long drags of part throttle boosting, non wot=(leaner).

Low-Speed
06-25-2019, 02:19 PM
The maximum safe power on most turbocharged vehicles will be around .80-.85 Lambda. The stoichiometric point of pure gasoline is 14.7:1 which would equate to about 11.75-12.5 gauge AFR (assuming you're using a wideband set up or configured to calculate AFR from the measured stoich Lambda point of pure gas). You can run a little leaner (say up to around .90 Lambda) on naturally aspirated engines for max power and on some less efficient forced induction cars should run a little on the richer side of that range. Our stock turbo would fall under that category. Also if you live in an area that has 5 or 10% oxygenates added to the gasoline that will probably lower the stoich point to around 14:1 and therefore a max 11.2-11.9 AFR using that .80-.85 range.

The leaner you run it you might make a little better power but the risks can be pretty high. I doubt the turbine and manifold would be the first to let go in your car. More than likely it will be stock cast eutectic pistons and more specifically the top ring land getting weakened by excessive EGT's and the occasional knock the engine will still see under normal operation. Now if you get a fast acting thermocouple and EGT gauge and are seeing a max of ~1650-1700 on the hottest cylinder when you're running high boost on the top end of the rpm's with lower to mid-12:1 AFR's then I'd say you're in good shape. But I'd highly doubt you're running that cool on a leaner than 13:1 AFR.

So if you're comfortable with possibly cooking the engine, not just the turbo, then keep pushing it. If that is a concern you might want to dial back those AFR's, install a water injection setup, or preferably get an EGT gauge so you will know if it's safe or not. If you do eventually upgrade to a bigger aftermarket turbo then you might be able to get away running a little leaner since you'll more than likely be running a much bigger exhaust housing and turbine wheel that won't have as much exhaust back-pressure.

Last note is I'm hoping your air/fuel ratio's are out on the street and not from a dyno session. The dyno doesn't load the car as much and most inertia Dynojet-style dynamometer's will read about half a point richer than the car is actually running out on the street for the SRT-4's. Somewhat related to that is if you're doing street tuning and using the DRB-III you'll have a lot of info to work with. But if you plan on dialing it right up to the maximum and don't have a scan gauge installed you won't always know what knock retard is doing. If you drive to different elevation or load, atmospheric conditions change, you get a little worse batch of fuel or any number of other conditions it's easy to push it right over the edge. Running too lean and too hot with a sudden spike of knock is all it takes to kill something.

I'll know if it knocks. The DTEC's Knocklite detects the slightest knocking. (And, according to the DRB, it's pretty damned good at it's job!)
I'm at about 12.7 at one point in the range on the AFR's. Everything else is currently lower. I plan to get it to 13.0 again eventually (Primarily for a dyno run!). As I said, I'm currently mid to high 12's. All street tuning.

DRB is a great source of info. Non-oxygenated 93 octane gas FTW!

I'll probably shoot 12.5 for a street tune. Then lean it out a little on the dyno on a second map. Gotta put down the big #'s for the locals, ya know?

Low-Speed
06-25-2019, 02:23 PM
Something else I found interesting:

The DTEC has a # for knock level. An indicator. I never was able to correlate what that # was. Nobody ever said it was degrees of knock retard, etc. But, as best I can indicate, that is almost the precise number it gives. Just as the DRB shows 4-5 degrees knock retard when you punch HOM on pump gas, the DTEC shows 4-5 on it's knock level sensor. Can anyone confirm similar results with the DTEC? Or is this just a pure coincidence?

Stage2BlackSRT4
06-25-2019, 02:34 PM
Off topic but when I was just stage2 I found that any more knock timing retard then about 5 and it would kick me out of the HOM and reduce timing (limp)

I don't know how you guys street tune, here in WA there are cops everywere. I don't dare risk more then a short 30-80 pull when getting on the freeway every now and then even then every few times I try that I've seen a state car soon after and been like...ops that was close..going to have to dyno tune it

Low-Speed
06-25-2019, 02:55 PM
Off topic but when I was just stage2 I found that any more knock timing retard then about 5 and it would kick me out of the HOM and reduce timing (limp)

I don't know how you guys street tune, here in WA there are cops everywere. I don't dare risk more then a short 30-80 pull when getting on the freeway every now and then even then every few times I try that I've seen a state car soon after and been like...ops that was close..going to have to dyno tune it

I saw the same. It immediately goes to 4-5 degrees KR, and kicks off HOM at WOT with pump gas.

I happen to have a few roads I can tune on. 3 and 4 mile straight stretches, with no houses, nothing. What was probably a logging path, that ended up getting paved. And there are not a lot of cops around. Especially not state guys! So....It's not so bad. Plus, there's a good number of back-roads if you will, with plenty of room to hit 100+....

I know to work on getting the boost up some, and go from there.

Low-Speed
06-26-2019, 07:32 AM
Does a spike of just over 20 seem pretty normal for stock, before hitting knock?

blackbird
06-26-2019, 09:33 AM
First define what type of "spike". There are two common descriptions of a boost spike. I call a spike when your boost control setup allows for boost to quickly and sharply overshoot the desired goal and then immediately oscillates and/or settles back down. That's the most widely used definition of a spike but a lot of SRT-4 owners have taken to calling the stock turbo's behavior a spike where boost builds up fast and high and then starts tapering down as exhaust flow gets choked off in the higher rpm's.

When you say normal for "stock" I also wouldn't call your setup stock. You may not have a lot of little modifications but you've got a lot of big items covered. The S2 completely replaces the computer/injectors/sensors, the AGP WGA can have a lot higher spring pre-load/tension on the wastegate flapper, and a piggyback (DTEC) is a very big modification. Now if we take a bone stock, as it came from the factory car and put on an aftermarket WGA the stock PCM controlled boost via the factory boost control solenoid might not be able to compensate for the extra spring tension fast enough and it will spike. Most WGA's call for using a simple bleed that can completely bypass the factory boost control or use an alternate boost controller. In a case like that the stock PCM will generally get unhappy when you go over the stock 2.25 BAR MAP sensor limit of around ~18 psi.

Now on your setup with S2 you've got a computer and MAP/TIP sensors that can read up to about 29 psi of boost. Since you mentioned using the dial-a-boost function I'm assuming you've got the S2 WGA replaced with the AGP but are on an otherwise stock (S2) boost control setup. The AGP should have a stronger overall spring tension that should allow for higher overall boost but it probably also starts to ramp up sooner and "spike" like the second definition given above. If you're just rolling into the throttle or going WOT and it builds quickly to 20 the computer may not be expecting that and may not be getting enough fuel momentarily. Combined with higher cylinder pressures you will get knock. And yes I've seen it a lot on stock turbo cars.

It's similar to the widely complained about part throttle boost (PTB) which is mostly caused by having an inadequate boost control setup on top of a small, restrictive turbo that spools extremely fast. You need a WGA with a high internal spring tension to hold the wastegate flapper shut to maintain boost as the exhaust backpressure starts to build in the manifold at higher rpm's but that also makes it difficult to control boost down low when there isn't that excessive backpressure present and the WGA tries to close the flapper, boost jumps up, and the computer cycles the factory boost control solenoid in an attempt to send a boost reference signal to the WGA to open the flapper and bring the boost back down. If boost suddenly ramps up to 20 pounds when you partially dip into the throttle the computer can increase injector duty cycle to compensate (since you're not at high rpm's and there's available duty cycle) but it isn't expecting there to be that much boost in the first place. You get a situation where it's just too much boost for fuel octane and you will get knock. The computer will try to retard/lower timing to bring it under control and all may appear to seem well as boost comes down and you continue with the pull. But remember you are initially getting knock and the computer has to see it before it can correct for it. If you're also running 12.5 to 13:1 AFR's or higher and start combining that "slight" knock it can eventually take its toll. That's just one more reason to be careful. A dyno queen is nice but too many people have blown things up trying to get the biggest numbers out of the least amount of stuff/modifications.

Low-Speed
06-26-2019, 10:22 AM
First define what type of "spike". There are two common descriptions of a boost spike. I call a spike when your boost control setup allows for boost to quickly and sharply overshoot the desired goal and then immediately oscillates and/or settles back down. That's the most widely used definition of a spike but a lot of SRT-4 owners have taken to calling the stock turbo's behavior a spike where boost builds up fast and high and then starts tapering down as exhaust flow gets choked off in the higher rpm's.

When you say normal for "stock" I also wouldn't call your setup stock. You may not have a lot of little modifications but you've got a lot of big items covered. The S2 completely replaces the computer/injectors/sensors, the AGP WGA can have a lot higher spring pre-load/tension on the wastegate flapper, and a piggyback (DTEC) is a very big modification. Now if we take a bone stock, as it came from the factory car and put on an aftermarket WGA the stock PCM controlled boost via the factory boost control solenoid might not be able to compensate for the extra spring tension fast enough and it will spike. Most WGA's call for using a simple bleed that can completely bypass the factory boost control or use an alternate boost controller. In a case like that the stock PCM will generally get unhappy when you go over the stock 2.25 BAR MAP sensor limit of around ~18 psi.

Now on your setup with S2 you've got a computer and MAP/TIP sensors that can read up to about 29 psi of boost. Since you mentioned using the dial-a-boost function I'm assuming you've got the S2 WGA replaced with the AGP but are on an otherwise stock (S2) boost control setup. The AGP should have a stronger overall spring tension that should allow for higher overall boost but it probably also starts to ramp up sooner and "spike" like the second definition given above. If you're just rolling into the throttle or going WOT and it builds quickly to 20 the computer may not be expecting that and may not be getting enough fuel momentarily. Combined with higher cylinder pressures you will get knock. And yes I've seen it a lot on stock turbo cars.

It's similar to the widely complained about part throttle boost (PTB) which is mostly caused by having an inadequate boost control setup on top of a small, restrictive turbo that spools extremely fast. You need a WGA with a high internal spring tension to hold the wastegate flapper shut to maintain boost as the exhaust backpressure starts to build in the manifold at higher rpm's but that also makes it difficult to control boost down low when there isn't that excessive backpressure present and the WGA tries to close the flapper, boost jumps up, and the computer cycles the factory boost control solenoid in an attempt to send a boost reference signal to the WGA to open the flapper and bring the boost back down. If boost suddenly ramps up to 20 pounds when you partially dip into the throttle the computer can increase injector duty cycle to compensate (since you're not at high rpm's and there's available duty cycle) but it isn't expecting there to be that much boost in the first place. You get a situation where it's just too much boost for fuel octane and you will get knock. The computer will try to retard/lower timing to bring it under control and all may appear to seem well as boost comes down and you continue with the pull. But remember you are initially getting knock and the computer has to see it before it can correct for it. If you're also running 12.5 to 13:1 AFR's or higher and start combining that "slight" knock it can eventually take its toll. That's just one more reason to be careful. A dyno queen is nice but too many people have blown things up trying to get the biggest numbers out of the least amount of stuff/modifications.


Semantics.

I'm on a direct setup with the WGA. No Solenoid. No boost controller yet. I'm only holding 14@ redline. I increased the spring tension, and the initial "spike" is now @ about 20 psi. (a little over on the gauge, not much) At about 21ish, it showed light knock initially. That means that for the rest of the run, it's using a lower timing, and pumping extra fuel, as it saw knock. Having backed it off a little, and testing on a fairly hot day, I'm confident that's about it. Was just curious what others have seen with their stock turbo setups. (Non PnP'd.)

Stock o2, downpipe, IC, and most everything else that affects knock levels is stock. A Big FMIC, i.e., will reduce knock tendency dramatically, as the air will be a LOT cooler going into the motor. As would a ported exhaust mani. And a 3" o2 housing, no Cat, etc.....

And, the S2 would tend to contribute to knock, since, as you stated, it runs the highest timing of any of the computers.

I'm thinking that's about as much air as one can flow through the stock exhaust mani without super-heating it! It's like, one little bit more, and it sees knock, with much higher IAT's....so....I'm guessing that's about all I'm gonna get out of it, without getting a 3" o2 and exhaust, and big FMIC...

I'm not crazy. One little orange flash and I let go of the throttle. I try to adjust slowly, so as not to see red flashes on the Knocklite. I run my Knocklite on the most sensitive setting! Bumps occasionally set it off!

I'm keeping my AFR's about 12.5. I'm not as concerned with knock because we do have good fuel here, and I have a way to tell if it is knocking!

The computer has no control over the boost. The car runs MUCH better that way! I was kind of surprised. Thought it would hurt the driveability. Quite to the contrary, it seems to have helped immensely. And I'm currently set up on the boost for very hot ambient temps. I could pump a little more on a cool day obviously. But with 90-95 (as high as you'll get here generally) ambients, my IAT's are about 120. I didn't think that was too bad for the stock IC.

blackbird
06-26-2019, 10:33 AM
If you have it set up that way then your dial-a-boost will not have any affect so leave it on "0" and surprise unsuspecting SRT-4 owners who know what it is that are riding in your car. :lol:

If you get a touch of minor knock and it's only pulling a few degrees timing out at the beginning of a run the stock/Stage computers will feed essentially all of your timing back in by the time you reach the top end. If you get heavier knock then you'll see a lower amount across the entire pull as the PCM will start to go into a long-term correction.

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