When running 26 PSI boost with a 20g is it normal to only have 3-5 degrees of timing?

[njdaewoo]

I have a 20g turbo and i recently increased the boost from 20lbs to about25-26lbs. I noticed i get 3-5 degrees of knock so i brought the timing down. My timing is at about 3 degrees at 5-7000 rpms. If i run my timing any higher the knocking starts I use 93 octane fuel all the time so i was just wondering if extremely low timing the norm when running higher boost?

 

[Black95TSIawd]

What kind of intercooler do you have? How are your AFR's? 26psi might be too much boost for regular pumpgas. Try lowering it to 22-23psi, check AFR's, and then raise your timing to where you don't get any knock.

 

[black_gst]

also how is you exhaust.. im running a 20g and was boosting 24-25psi as well and could only get about 4* of timing. it turned out that my muffler necked down to 2" inside and that was enough to cause problems

 

[njdaewoo]

I have the Punishment Racing intercooler, AFR is at 11.3 to 1 from about 4500rpm until 7000k. My exhaust is the thermal R&D 3 inch exhaust and the down pipe is Punishment 3 inch from turbo to cat back.... No cat

 

[Ceddy]

Running 3-4 degrees at peak of spoolup(3000-4000 rpm) is fairly normal.

Running 3-4 after spoolup(4500-8000 rpm) is going to cause majorly high EGTs, to the point of burnt valves, etc. Running 16* at high rpm at WOT is more normal.

 

[danl]

Less boost and less fuel............

 

[dsmdeliveryboy]

The timing is so retarded because you must be getting a lot of knock so turn the boost down before you get detonation..

 

[toofast82]

with 3-5cts of knock, your ecu wouldn't be retarding timing anymore than like 2*.
But yes having only 3* of timing advance between 5-7k is not where it should.
Stock 2g timing map would have around 11* at 5k rpm at highest load level without any knock.
Yes with 93 pump, it doesn't like much timing before knock occurs when trying to run high boost.
I recommend trying to retune for around 23psi to see if you can run a reasonable amount of timing before you burn up valves or something like ceddy said

 

[njdaewoo]

Thanks everyone for your input... I dropped the boost back to 20psi and now I have my 11 degrees of timing with no knock. At this point I will now try adjusting the boost up about 1 lbs at a time until i find a point I can keep my timing above 10 degrees.

 

[JayRolla]

I would richen the AFR up a little. 10.9 is where I was able to get the most boost when running pump gas.

 

[KeelesKustome]

have you noticed a vast improvement with this turbo? give me your thoughts on the whole swap, as i need some imput, I'm having a hard time deciding if i wana go with the 20g.

 

[njdaewoo]

have you noticed a vast improvement with this turbo? give me your thoughts on the whole swap, as i need some imput, I'm having a hard time deciding if i wana go with the 20g.

This turbo was night and day from stock but I have only used this turbo. I really cant compare it to any other. I do know that if i adjust the Mbc, the boost will easily go to 28 lbs by about 3800-4000 rpm range. Im having major problems with engine knock while increasing the boost from 20lbs to about 26lbs...

Also, I had to remove the main fan because of a clearance issue. The AC fan was good to go

 

[olmytsi]

You cannot run that much boost on pump gas my friend...

Either:

- turn the boost back down
- run some kind of injection (meth, water)
- run e85


You will kill your engine/headgasket if you keep knocking that much!

 

[turboglenn]

+1 to olmytsi... the only way people get away with running those numberson pump gas is with rediculously low timing numbers up top, which not only hurts the performance for the amount of air your flowing, but your letting that gas go right out the valves and through the turbine while it's still burning, which as stated will at minimum burn your valves up.

There's several "case study" style papers people have done on the effects of ignition timing and boosted engines, with the general consensus being that if you have to take the timing any lower than 20* BTDC you need to run less boost or a lower compression ratio. Now even in stock for the ECU deviates from this when it pulls timing to 9* when the boost hits (2g ECU does anyway), but it's still programmed to aim for the 20* by redline (the more RPM increases the further the timing should too in order to keep the burn cycle completing at the proper time for what's called peak cylinder pressure, which should accur between 15 and 20* ATDC for the best performance

 

[Thomas91169]

what sort of fuel system and tuning apparatus do you have to support that 20g @ 25+psi?

 

[KeelesKustome]

what camshafts would you recomend for a Buschur Racing 20g turbo This turbo is ported and clipped that i just baught?

I have an automatic that will be staying auto, would a mild cam upgrade be preffered so i can keep a lil power down low for DD or is their a better cut out their

 

[olmytsi]

I personally recommend HKS 272's or GSC S1's ( I run GSC S1's on a 50 trim setup which is similar in flow to the td06h 20g).

There are ALOT of cams out there for our cars (probably more so than any other car model out there) so you will have LOTS of suggestions on this.

Some are cheap, some aren't; my GSC's were $550+ but I LOVE them. You can get some cams brand new for around $350 or so (not sure about exact pricing).

 

[KeelesKustome]

I'm in the buying parts to build process. so does the 20g need a jpipe or anthing of that nature?

 

[njdaewoo]

what sort of fuel system and tuning apparatus do you have to support that 20g @ 25+psi?

Just the items listed in my Signature... I'm kinda wondering, whats the purpose of buying a 20g or any (larger) turbo if you are limited by the fuel. I think I would have been better off getting a 16g with all the bells and whistles and running that. It seem like a lot of us want a 400hp car but the fuel kinda limits your true power levels and Im talking about daily drivers. In Jersey, I have never seen a E84 station around here. I guess im just SOL..... .. With my new cams (comp cams severe stage 2s) it also seems I get more knock after the cam install. The first thing I noticed was my car seems to run hotter while I cruise around. I never had that problem with my stock cams and with the stock cams my timing at red line was closer to 17 degrees.. After installing the cams and new timing belt, I timed the engine and I made sure all the marks were lined up. I rotated the engine several times and it always came back to perfect timing. My cars power level seems extremely strong at about 3800-5200 (full boost 20lbs, is at about 3800 rpms) with 7 degrees of timing (in this rev range I cant go any higher) and then the knock starts. Some days the computer is removing 4-6 degrees of timing once the rpms climb to 5k and above (boost is 20lbs at this rpm range and timing can only advance to about 8 degrees because im having these knock issues). I took timing out in the upper ranges but now Im at about 6 degrees max at 5 - 7k rpms at 20lbs of boost.
The 20g turbo on my car has always ran 20lbs with very little knock issues since I installed it back in January 2010. Now after the cams install and running 20lbs I cant get rid of the knock unless its down to 6 degrees timing from 5k till 7500 rpm. Im still puzzled as to whats going on here..

 

[VETTE_50_TH]

What kind of fuel are you running. Cant believe no one asked this yet.

 

[njdaewoo]

What kind of fuel are you running. Cant believe no one asked this yet.

93 Octane Exxon or BP, I have tried different gas stations but the problem still persist. WTF

 

[VETTE_50_TH]

What are your IAT's like?

 

[donniekak]

I'm guessing you have a td05h 20g. A td05h turbine, high boost, and pumpgas are a bad combination. Out here in the heat, 115* and up, my evo3/e85 setup worked better than most large turbo cars on 91 octane.
It's a 2 liter. Only way to make big power on low octane is a large hotside, and the lag that comes with it. Remember you are running the same turbine the car used for a stock 195 crank hp.

 

[VETTE_50_TH]

Im going to say your base timing needs to be checked.

 

[njdaewoo]

Im going to say your base timing needs to be checked.

Agreed, my air temps are in the 70s-80s range.. I installed a home made cold air induction before the summer temps started.... It picks up air in front of the tire

Here is a DsmV3 log:

I'm guessing you have a td05h 20g. A td05h turbine, high boost, and pumpgas are a bad combination. Out here in the heat, 115* and up, my evo3/e85 setup worked better than most large turbo cars on 91 octane.
It's a 2 liter. Only way to make big power on low octane is a large hotside, and the lag that comes with it. Remember you are running the same turbine the car used for a stock 195 crank hp.

I think my Hotside is 10CM... you can check out my complete turbo setup at this address:

Hahn Racecraft - Turbo Upgrades and Parts