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BW S3 problems

6K views 53 replies 13 participants last post by  Zenkat 
#1 ·
Didn't know where to post this exactly. It's technical, and a bit of a story.

So, background on the car so people can understand where it's at:

Used to be a 47lb S3 setup on e85, and made a little over 450 to the wheels on a stock (somewhat hurt) motor, with 27-28psi and 33-35* timing. When the motor went it was time to build it to support that power and more.

Current build:
e85 (bosch in-tank setup)
8.0 je pistons, eagle rods w/625s
Strap kit, IJ windage/scraper
Ported/built head from bob@ravenworks (+1/+3)
externally gated S3 w/58lb wheel, td06hr turbine
tial external bov
shortram, 3" exhaust, big intercooler, etc
Crower S2 cams (switched to) BCS3

In the beginning of the tuning, i was using a 14.5lb setup in the WG, which we didn't push too far in regards to boost, and was able to handle around 25* of timing. Upon moving to a 16lb setup, the timing wanted to come down (excessive knock, turn timing down, less knock).

At 26psi (wgdc maxed), the car would only demand 18-20 degrees at most (and still knocked a little). It was a 400whp car at this point. Not dyno'd, just a comparison of cars i'd raced while at this point in the tuning.

The prematurely maxed boost, low timing, low compression in cylinders (125), slow spool led Nigel to believe the cams were too big (totally right, was a bad decision to use Crower S2).

Recently switched to BCS3 (on the same tune for the CS2 still, mind you), and the car felt peppier at lower RPMs (compression is up to 135 now). Upon WOT, the car has started knocking even worse, bringing timing as low as 14* at 26psi on e85. The current knock is always at 5000-5500. (and was at that spot before the cam swap)

WGDC are still maxed out. I need to do a wg line and solenoid test just to make sure it's properly functioning, but thats only 1 issue.

I'm no genius at reading plugs. I've been told an assortment of metal looking specs in the porcelain are a sign of knock. Not knowing if the sensor is being legit, i've been constantly trying to read the plugs (and seeing specs). Have tried copper, 1step iridium, and 2step silver plugs, which all yield the same results as far as how the car behaves.

This isn't a knock at Duster, the current tuner. The man knows how to tune cars. I'm just at my wits end with the real/false knock and don't know where to go from here. The money i've spent trying to make this huge S3 run like a monster is ridiculous.

If you have questions, ask away. I'm sure i've left out information that people need.
 
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#4 · (Edited)
To be different, and because it was the easiest thing to move into. When the car died, the option was there to upgrade the already upgraded S3 for cheap, and to keep the stealthy/stockish look. I realize almost no one has gone this direction, so it's new territory. But on stats alone, this turbo should be making massive power with no problem.

If the turbo really is the problem, then maybe i should have gone big and sold it awhile ago, but the original plans have changed a bunch in the last 2 years and i'm doing what i can with what i have and trying not to spend a fortune more to get to my goal.

I can't check EGTs, but IATs are fine. The cams were put in as you would any cam, centered at zero on the gears and TDC. I've heard Nigel prefers to use the cam fixture tool. I don't know if that would make a difference or not. Playing with cams is not my forte.
 
#3 ·
That sucks. I'll be going EF2 this summer, hopefully all goes well. Although my built longblock will stay untouched through the switch.

Anyway to check EGTs? IAT looks ok? How were the cams tuned?

5000-5500k is a bitch spot.
 
#6 ·
Seafoamed the intake, tested the car while trying to burn off the seafoam, and the car is giving some timing back. Weirdness. It knocked a little with advanced timing, but was seeing 22-23* instead of sub 18. I dunno what to make of it.
 
#8 ·
I was getting gunk on the injectors, investigated and realized my feedline and part of my returnline i'd built was not e85 rated. Swapped it out with good stuff, had the injectors cleaned and tested. But did not bother to clean out the intake at all. Figured if there was junk it would have burned off by now. I dunno, but it makes me happy that it's not acting as awful at this specific moment in time.
 
#10 ·
So i threw the car on a dyno this afternoon to address some issues, test boost with both lines on the wg, and use a new set of 4306 with very advanced timing to force the car to do it's knocking thing.

Timing was around 28 (before knock). It knocked 5* on a 3rd gear pull, took it to 7k and shut the car off. Only 2 of the plugs had any marks on the porcelain. You tell me, do these spots look like detonation? Appropriate detonation for 5 counts registered?





The other issue was weird. I believe it was a dyno dynamics i was on, with adjustable load. Whatever the case, the car would only do 21-22 psi on the dyno (and easily does 25-26 with pulls on the street). Doubled the load that he thought the car should have, still the same.

Here's a pic of a few 3rd gear pulls at 21psi, timing advanced 4 degrees, 0.5 knock at most. (23-24*)


With all that said. What's a good method that people prefer when trying to push 35psi or more? EBC? MBC? Anything specific. I'm certain now this car will not do what i want on PCM boost and needs to be changed up.
 
#16 · (Edited)
So i threw the car on a dyno this afternoon to address some issues,

The other issue was weird. I believe it was a dyno dynamics i was on, with adjustable load. Whatever the case, the car would only do 21-22 psi on the dyno (and easily does 25-26 with pulls on the street). Doubled the load that he thought the car should have, still the same.

Here's a pic of a few 3rd gear pulls at 21psi, timing advanced 4 degrees, 0.5 knock at most. (23-24*)


With all that said. What's a good method that people prefer when trying to push 35psi or more? EBC? MBC? Anything specific. I'm certain now this car will not do what i want on PCM boost and needs to be changed up.

WgDC was completely maxed out throughout the entire dyno pull but boost curve was crap. At 4500rpm, you lost a good 8psi on the dyno. The odd/slow/low boost curve and near absence of Knock sure makes me think the Dyno load was way off.

imo plugs look clean
 

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#13 ·
I do have boost by gear thru PCM, and an external gate with 16lb spring. Car has maxed out WGDC at 26psi.

You could try a boost box. Do you have a WOT box?
I do have a wotbox, but doesnt a boostbox limit at 29? I realize it utilizes the factory wg solenoid. Have not investigated them very far. Asked Duster about it, but as he said, if the wgdc in the pcm is maxed, the boostbox would be too? I think that's how he put it.
 
#19 ·
Yeah. He set the dyno load to what he figured the car should have, based on experience with other cars/weights. I had him double the load just to see if it affected boost, but it did not. I dont like that dyno. I'll probably head to a fat-wheeled dynojet soon just to test again.

Knock levels with the advanced timing were about the same, dyno vs. street (5-6 counts). But the street gives me 25-26psi.
 
#24 ·
Is it possible to adjust the gears, have the compression go up, and have the car lose bottom end? Cuz that's what happened when i touched it.

Static compression was at 140. I started with going neg on the intake, which improved it quite a bit. -3 yielded 148-149 compression. I then tried the exh side, but -2 to +2 yielded all the same results. Didn't know what to make of it, so i left it at -1 i believe.

Car felt much worse. Spool was noticeably slower. Vacuum also went from -13 to -11/-12 after the changes.
 
#27 · (Edited)
Your KR issue sounds EXACTLY like mine. Here is my setup...

Stock bottom end/stock head
Crank was checked/cleaned
Brand new stock rods/pistons
Head was decked/new guides
e85/walbro 255/6an/Dusters 1025cc injectors/rescale
Holset HX35/log/tial 38mm 16lb spring
boostbox/aem solenoid/3bar
ngk 4306

I originally had a BW s251 rs on here hoping to make it a torque monster with e85 and high timing but my plans were shit on by this knock retard issue. When I swapped over to the e85 rescale and started to make power the motor had about 2k miles on it. ZERO issues...ran beautifully, compression was either 165 or 170 across the board. No odd noises nothing...

Basically I got into the 20-24psi range and started to slowly increase boost from there and logging - the rescale (I don't recall the exact numbers been a year) was originally hitting around 32-34* timing advance and right around 4500-5500 I would just get ridiculous amounts of KR seemingly out of nowhere. 2-6* KR was pretty typical - always in that section - nowhere else.

If I lowered the timing with the DSP by 4-8* it would basically be gone - occasionally it would log 0.5-1* KR - but so would all that torque. I was settling for 20-22* TA on basically a BW S3 turbo. Here is everything I tried...


Re-torqued the knock sensor with 2 different torque wrenches, 1 digital. Teflon taped bolt threads, under torqued (hemi spec), new knock sensor, fresh ngk 4306, various gaps, 2 step colder platinum plugs, 1 step colder iridium, removing items from the bay that could vibrate, preventing my exhaust from hitting the frame, securing my WG dump (tube originally rested on k member, flex pipe).

This issue killed my enjoyment of the vehicle for the entire last years season...I've just been driving it waiting for the fucking motor to explode but it just won't die...it's got about 12k miles on it now, my signature HX35 w/ .63 hotside, 93oct and 28psi - still won't blow up, KR (4500-5500) like a bitch unless I drop the timing substantially.

Since I'm nothing more than a back yard mechanic I'm assuming I screwed up somewhere in this build (4th motor I've ever assembled) - didn't skimp on any machine shop work, re-use worn parts, red flags get thrown during built for clearance of fitment issues. Everything was brand new minus the block, crank and refreshed head. Here are the only 2 theories I've come up with that would make sense...CAUTION: I DONT KNOW WHAT IM TALKING ABOUT

1) The honed stock cylinder for brand new stock pistons has somehow created a huge PTW clearance and now they rattle under strain? wrong I know

2) I didn't put a windage tray in - I left the stock balance shaft assembly intact. Perhaps something in there is rattling around like mad...

Sorry if this sounds ranty - my ass is still sore from this thing ruining my past year of motoring lol.

Edit: I spoke with Duster on this briefly - he said if lowering the timing fixed the issue then its not phantom knock - forgot to add that.
 
#28 ·
Yeah, same here. Lowering timing reduced the knock the car sees. But i'm having a hard time believing it's real. Retorqueing my sensor (from like 190 to 195, maybe even less of a change), plus seafoaming the intake helped. Took off the BOV today to put a stiffer spring in for the higher vacuum, and saw a lot of oil coating it and some inside the coldside.

Car is just annoying me with all its problems.

Also, tonight, i've moved the cam gears the opposite directions and compression went way down. So, negative on intake, car feels like crap, positive on intake, lose compression. I dunno what to say to it. Just gonna stuff stiffer springs in the WG and live with the timing it's got so far.
 
#29 ·
Decided to ignore the compression loss and went with +2int/-1exh. The opposite direction i went from yesterday. Compression was probably in the 135 range, but vacuum came up to 14/15 instead of the 13ish it was at 0/0, or the 11/12 it was when i went with more compression.

Also shoved 22lb worth of spring into the wg, and got the car to boost about 29-30. I just don't get how people can boost into the 30s. This car refuses to get up there.

Partial success, though. Car felt pretty strong, even with the knock readings bringing timing back under 20.
 
#30 ·
Well, took the car for final cam gear tuning. Upon going negative with the exh gear, it starting knocking far less. The man who owns the shop is very good at listening for knock, and heard none, when the car would complain about some.

Can't fix the spool, or the low boost (which is a side-effect of the spool). But with max advanced timing it put down some ok numbers. If i can get the knock sensor turned off or down, it should do ok tomorrow at the 1/2 mile race.

Here's the best run with no knock compared to how my stock block 47lb ran nearly 3 years ago. (red is 47lb, blue is current 58lb)



I'm selling it after this. It obviously prefers a car that isn't as fully built as mine. I think a stockish motor would have better luck with this setup.
 
#35 ·
I left the stock cams in even with the stage 1 head and built motor...hoping to avoid this type of issue on the new car.

My silver car had a slow spool issue after the build. I put higher compression pistons (8.8, .020 over) in with a light exhaust port on the head and Crower stage 2 cams using stock cam gears. Everything else was left the same (GT3076r, fuel, etc.). The low end was gone but it pulled like crazy up top. I sold the car telling the new owner to get cam gears and get a tune. He got a tune and it made more power, but less torque by over a hundred lbft! Until the he gets the gears, I'm at a loss as to what the issue is. Maybe the head porting isn't matching up well with the cams too.
 
#36 ·
That's a bit discouraging...I'm swapping to a CNC Port head and cams to match my turbo size, with gears and a dyno tune to go with it - does this happen to every car? I don't think I'd be happy if my turbo spooled any slower than it already does...
 
#38 ·
I gotta say, even at the power level it's making, this car pulls and pulls up top. I just attended a 1/2 mile roll racing event out here with some pretty stout cars. I was consistently hitting 152-155mph by the end.

Surprised a lot of people with it. Even got to race a new auto hellcat, and held him at my rear panel the whole time. He said he was also running 155mph.
 
#45 ·
Yeah hopefully I dont have that problem . I got the same setup butk mines a 47 with the td06 turbine . I was hoping to bust 500hp , I want all of it damnit . I dont know if that will happen but we will see . Atleast I can get a nice 10sec pass
 
#50 ·
Looks awesome man , What setup is this one ?
 
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