advanced knock issues

[futurevr4man]

i know it sounds ridiculous but there really isnt. i know there are individuals around lex who would sell it to you for an arm and a leg but...

i am gonna try the timing with him and see what happens first. my friends go to the strip like every week, so ill get him to put in a few gallons next time he is there to see what happens

[neverenoughhp]

Yup. Most tracks have it.

the boost should not be coming on around 3300; it should be just about full tilt by then. 17 psi with that set up should definitely be in the right ball park for knock free power. Possibly even 18 psi since you are running a piggy back and 450s. I ran 17 psi with 16ts, fmic, and 550s and made 430 awhp with a few extra mods. 400 awhp shouldn't be hard to hit. Good luck. Who is the owner?

[dpartinvr4]

what do his IDC's look like?

[futurevr4man]

Spddemonvr4 is his name on here. He is very knowledgeable about these cars as well but he doesn't post much on here and I am trying to get some ideas that we are potentially missing.

The idc's are in the mid - high 90's.

I can't remember a specific time of boost. You are right that's it's probably earlier but the knock I know starts around the early 3k rpm's

[SpdDmnVR4]

Alright, I'm tired of stalking a thread about my own car...

boost comes on early (14 by ~3000), Knock begins about 3300-3800ish and will hold steady once it hits ~8-12 counts. Occasionally, I have seen knock as high as a 20 count, but it is usually much lower. The car will attempt to correct by dropping timing according to the logs but it is not enough. According to AEM wide band, the only way to keep the knock away is to drown it with fuel (10.0-10.2) rolling some coal out the back -_-

My duty cycles are right at 95-98% and my pulse width is down about 19.5 ms (thats the highest I have seen while logging). Pertinent knowledge of the car includes 92 VR4 (cast crank, stock factory OEM longblock), 16T's, catless TBE, 450's, Walbro (non-hotwired), SAFC, DCFMIC (stock IC piping), Halman MBC @ 14 psi, AEM Wideband (bung after the front/rear joint of the DP), HHH datalogger, Base timing set right on 5 degrees (Peak in third gear on a clean pull is right about 17-18 degree according to HHH).


This weekend I am putting on the SAFC2, Greddy EBC, and wiring the Wideband output to my EGRT pin. Will also be doing a full Boost leak check and likely a compression test/pulling the plugs for inspection.

Other issues the car is having right now: It needs motor mounts and carrier bearings. The idle is sometimes a little bouncy (1200-1400 RPM but will idle down to 1000 after sitting at a light for about 30-40 seconds). Idle is about 15.0-15.2, but will sometimes randomly dip down into the 16's. Cruising, it runs between 14.5-15.0. Only other problem is if the car sits in heavy traffic for a period of time, it will get caught between open and closed loop under constant throttle and ends up bucking pretty noticeably (AEM bounces rapidly between ~13.0 and ~16.0 in succession with the bucking).

The car does get driven daily and gets about 15,000-17000 miles/yr (currently 97000 on the car). It has been VERY reliable thus far. Even with the knock issues at the track last weekend, The car went a best of 12.74 @ 111.78 (knocked 20 counts on the big end) and 12.78 @ 113.2 (cleaner run, only 8 counts of knock).

I usually just stalk posts on here and figure out any issues/ learn from them. But I am really stumped on this. I have not adjusted base timing in either direction, I have not put higher octane fuel in, and I have not lowered the boost to see if it goes away. My combination of parts should be just fine up to ~400whp.

[dpartinvr4]

those IDC's seem high for walbro and 450's, what does your timing look like?

[SpdDmnVR4]

Timing is set at 5 degrees base (per factory) and according to the HHH logger I have 17-18 degrees peak @ WOT and 7000 rpm

[SpdDmnVR4]

HHH exaggerates IDC's btw. That's why I referred to the 19.5 ms peak IPW. Usually injectors are good up to the ~24 ms mark

[RealMcCoy]

HHH exaggerates IDC's btw. That's why I referred to the 19.5 ms peak IPW. Usually injectors are good up to the ~24 ms mark

Correct me if I'm wrong with the math, I'm just working from memory and the numbers rattling around my brain, but doesn't 20 ms IPW at 6000rpm = 100% IDC ?

[SpdDmnVR4]

I need to go back and check my facts I guess. I swore that HHH exaggerated IDC's. Anyways, I ran the stock 360s up to ~120% according to the logger and the IPW was about ~24ish ms. Never skipped a beat like that for about a year.