Car seems to pull harder at 3/4 throttle instead of WOT, wha?

[csosnowski]

So i was wondering if anyone has felt or experienced this issue?

The car has 185k miles, mods are in my signature.

Plugs are clean and properly gapped, no codes and I havent pulled logs yet because it really might just be in my head lol.

Basically what im searching for is any insight as to why it would seem like the car pulls harder when i dont have the pedal all the way to the floor. Ive searched but I havent found any conclusive info.

Also of note, it seems like there is quite a bit of soot in the exhaust tips. I washed the car the other day and ive driven about 500 miles and the whole inside and lip of the tailpipes is sooty. Could the main cats be clogged/failing?

Any info would be greatly appreciated!

[RedB5S4]

I'm on a GIAC 93 oct file and sometimes I'll get the same sensation that you do. Kinda like, accelerating moderately but not that hard and the boost just comes on more of like a surge. Pedal isn't even close to the floor, yet when I get on it, it doesn't quite have the same feeling. It's hard to describe but I know what you're talking about... Never really thought twice about it being a problem though.

As far as the exhaust tips go, mine do the same thing. If your main cats were failing you'd hear sort of like a jingle noise coming from underneath the car, especially when going over bumps and stuff. Gets really annoying. And I think you'd throw a cat efficiency code as well if it was.

[NishadJoshi]

Actually, I know what feeling you're talking about... I think it's all about what RPM/PSI you're at.

When pulling, I don't usually just FLOOR it... I try and find that sweet spot before going WOT.

[GunSupplier]

I honestly don't think anything is wrong. It's honestly just because K03s are so small that even 50-75% throttle is enough to get the boost to spike, especially in the lower gears. That results in the "surge" you feel. I get it too sometimes. I think it just "feels" faster to you because you're not giving it much gas. Unless you are getting misfires at WOT, I wouldn't worry about it. To really test this out a bit, try putting the car into say 4th gear and turn like ~1900 RPM, and then give it 75% throttle and let the RPMs and boost slowly climb. Then do the same thing at 100% throttle. There should be a difference, but like I said, working with such small turbos, a mouse could cough on them and get them to spool pretty suddenly.

I also get some soot on the exhaust tips, certainly if I drive 500 miles. I sincerely doubt that anything is wrong with the main cats. You'd know if they were plugged, as there would tons of hissing, possibly a bad/rotten egg smell and the car would be significantly down on power.

The root cause of the soot, I've determined is just that OTS Stage 1 tunes generally run a little bit on the rich side for safety. A slightly richer exhaust (I'm not talking about PIG rich, which would make your entire back bumper sooty) will be a little more sooty. Unless your exhaust is getting tons of soot caked on within 50 miles of driving, it's pretty much normal.

[csosnowski]

hey, thanks for the response redb5!

you hit the nail on the head, like if im cruising along in 6th and start to accelerate and then drop to 3rd but not full throttle it feels like i get to 90mph faster than if i rev matched and dumped it into 3rd @ WOT.

youre talking about the big cats or the precats? precats are gutted and the exhaust has somewhat of a hot-ish sulphur smell after driving the car for awhile, especially after some hard pulls.

any inkling as to if that is normal or a precursor to something?

EDIT: 2 replied before I returned reply

[GunSupplier]

hey, thanks for the response!

you hit the nail on the head, like if im cruising along in 6th and start to accelerate and then drop to 3rd but not full throttle it feels like i get to 90mph faster than if i rev matched and dumped it into 3rd @ WOT.

youre talking about the big cats or the precats? precats are gutted and the exhaust has somewhat of a hot-ish sulphur smell after driving the car for awhile, especially after some hard pulls.

any inkling as to if that is normal or a precursor to something?

My pre-cats are also gutted but main cats still in place, and after a hard pull where the exhaust is SUPER hot, mine smells a teeny tiny bit like sulfur, but nothing strong. Nothing to worry about, been like that for 40,000 miles for me. It just EVERY SO SLIGHTLY smells of sulfur, like barely barely there.

Like I mentioned, I just think these cars with the factory turbos and a tune are "peaky". Not in a bad way, just the way the car reacts.

[csosnowski]

My pre-cats are also gutted, and after a hard pull where the exhaust is SUPER hot, mine smells a teeny tiny bit like sulfur, but nothing strong. Nothing to worry about, been like that for 40,000 miles for me. It just EVERY SO SLIGHTLY smells of sulfur, like barely barely there.

ah, so its all probably in my head then. the smell isnt real strong, just a hint.

car pulls strong so ill probably not worry about it. probably going to purchase an exhaust soon and upgrade to APR's stage2 software unless i have some breakthrough in learning WinOLS or tunerpro.

thanks for the responses guys, i really appreciate it!

[csosnowski]

search "3/4 throttle mod" on various forums from 2002-2005

thats pretty interesting info, I didnt think the little k03's would lag like that. It does stand to reason though, when you pop open the throttle plate there is a pressure drop and the turbos have to take a second to catch up and fill the intake tract back up.

Whereas if i went 3/4 there isnt as much of a pressure differential and they wouldnt have to work as hard to fill the same area, very interesting indeed.

[RedB5S4]

Haha it's awesome to hear responses like, nope nothing is wrong with your car... run along now. 185k miles damn mengh

[csosnowski]

Haha it's awesome to hear responses like, nope nothing is wrong with your car... run along now. 185k miles damn mengh

thanks! ive been pretty fortunate with this car.

maintenance+ocd=185k and counting haha. timing belt and vcg's coming this summer.

motor mounts probably too...(if you read this Max@034, i should be ordering the mounts in a month or so; AZ discount? lol)

wife's car (A4) has 230k, gonna chip it soon lol! had a peek in the injector bungs on her car and the valves are clean as a whistle and no noise from the turbo.

[CruzS4]

i get that sensation too with my giac tune and a catback with k03s. i wouldn't worry about it

[phila_dot]

Get some logs. Could be timing retard. That would explain the soot too. Although, I think APR likely has mild timing.

[GunSupplier]

Get some logs. Could be timing retard. That would explain the soot too. Although, I think APR likely has mild timing.

True, it could be that, but I highly doubt it with his tune, or any OTS tune for that matter. Good tip for sure, though.

[csosnowski]

Get some logs. Could be timing retard. That would explain the soot too. Although, I think APR likely has mild timing.

good plan, im going to get some as soon as i can. school, work and small business are time prohibitive lol.

if the ecu is retarding timing, what can i do to reduce or eliminate this condition?

[jibberjive]

This ha, beat me to it.

search "3/4 throttle mod" on various forums from 2002-2005

[phila_dot]

True, it could be that, but I highly doubt it with his tune, or any OTS tune for that matter. Good tip for sure, though.

You would be suprised then. Some of the OTS "professional" tunes that I have seen are horrendous. Major companies too. I don't have any experience with APR though, and they aren't the lazy hack types, but you never know.

if the ecu is retarding timing, what can i do to reduce or eliminate this condition?

Anything to reduce knock. Better gas, intercooling, water meth, tuning. Basically, reduce IAT, engine temps, and EGT.

Is it only during WOT? How are your MPGs?

This is all speculation without logs though.

You guys are joking about the 3/4 throttle mod thing right?

[S-Power]

Funny this thread has come up because I was thinkin the same with my current setup. I put a brand new motor (Brand New Crank Motor 0 Miles) in a few months ago and got my stage3- 034 tune recently. Car hold 19psi throughout entire RPM's but sometimes when I WOT it freaking pulls damn hard and other times at WOT im like "WTF" my stage2+ felt the same.

034 has also told me that I am the first "bosch" MAF tuned stage3- car they had. The only thing that I haven't tried yet is replacing my Forge007 Springs because I have the green and need yellow. Im getting the feeling my valves are opening up to early.

Any Idea's or thoughts ?

[csosnowski]

You would be suprised then. Some of the OTS "professional" tunes that I have seen are horrendous. Major companies too. I don't have any experience with APR though, and they aren't the lazy hack types, but you never know.



Anything to reduce knock. Better gas, intercooling, water meth, tuning. Basically, reduce IAT, engine temps, and EGT.

Is it only during WOT? How are your MPGs?

This is all speculation without logs though.

You guys are joking about the 3/4 throttle mod thing right?

mpg's are decent 26-30 hwy, 18-20 city.

seems like it just doesnt have as much 'poop' at WOT sometimes. although it could be IAT's, ill pay more attention and get some logs and see what I can glean.

[034Motorsport]

motor mounts probably too...(if you read this Max@034, i should be ordering the mounts in a month or so; AZ discount? lol)

lol, I was skimming through this and swore I saw my name! Just send me a PM when you are ready and I'll see what I can do!

The reason you feel this is because it is basically true in many cases. It is called Drive By Wire, and it is the devil. It all seems fine and dandy until you drive a Drive By Cable car and realize just how wonderful it is to not have the ECU constantly trying to make decisions for you based on what it THINKS you want and what emissions need...

[csosnowski]

lol, I was skimming through this and swore I saw my name! Just send me a PM when you are ready and I'll see what I can do!

The reason you feel this is because it is basically true in many cases. It is called Drive By Wire, and it is the devil. It all seems fine and dandy until you drive a Drive By Cable car and realize just how wonderful it is to not have the ECU constantly trying to make decisions for you based on what it THINKS you want and what emissions need...

awesome Max, thank you. I already have trans mounts and rear diff carrier bushings from you guys and I really like them so im aiming to complete the set! Ill let you know when im financially able haha.

yeah the dbw isnt too bad in this car but it is noticible, i had a mk4 vr6 jetta that was sometimes painful to drive because of the pedal lag.

[ECS Tuning-Audi]

awesome Max, thank you. I already have trans mounts and rear diff carrier bushings from you guys and I really like them so im aiming to complete the set! Ill let you know when im financially able haha.

yeah the dbw isnt too bad in this car but it is noticible, i had a mk4 vr6 jetta that was sometimes painful to drive because of the pedal lag.

Yep, I was going to mention the same thing about DBW. By gradually applying the throttle the air flow is nice and steady and there isn't a drastic change in pressure as apposed to just slamming on the gas.

Jason

[phila_dot]

Yep, I was going to mention the same thing about DBW. By gradually applying the throttle the air flow is nice and steady and there isn't a drastic change in pressure as apposed to just slamming on the gas.

Jason

The ECU limits the throttle to gradually open to 100% by 4k rpms on stock tuning and all OTS tunes that I have seen.

With logs this can be confirmed in his tune.

Example:

[ECS Tuning-Audi]

That's interesting I never knew that!

Makes sense though, seams like its own way of optimizing the air flow with the boost spike from the turbos at low RPMs

I'd like to see that graph compare to a dyno graph and how the power is effected.

Jason

[csosnowski]

this makes sense, i think i can feel the ramp up like what is shown on that log.

i remember reading in someones thread about how they changed the throttle ramp to 100%@2k rpm and he was questioned about it.

it really doesnt matter to me though, i was mainly concerned that there was some impending doom coming to me and wanted to be prepared lol.

im going to get some logs soon i hope, trying to find a decent free logging program with a good sample rate.

my vag cable didnt seem to have the best resolution logging one block and with 3 its like syrup. any suggestions?

[034Motorsport]

this makes sense, i think i can feel the ramp up like what is shown on that log.

i remember reading in someones thread about how they changed the throttle ramp to 100%@2k rpm and he was questioned about it.

it really doesnt matter to me though, i was mainly concerned that there was some impending doom coming to me and wanted to be prepared lol.

im going to get some logs soon i hope, trying to find a decent free logging program with a good sample rate.

my vag cable didnt seem to have the best resolution logging one block and with 3 its like syrup. any suggestions?

Unfortunately ECU-X is basically the only easy to obtain program that allows high resolution logging. 30hz and above. It's not cheap either.

[csosnowski]

yeah that sucks. im looking into options lol.