The Case of the Underachieving 16G

[Quasimondo]

My setup:

16G, w/ ported manifold, housing, and o2 sensor, boost set at 18 psi.
FIC 650 injectors, Walbro 255 pump and aeromotive afpr, base pressure set to 45 psi.
Dejon intake and UICP
MAFT w/ Keydiver chip

Maft settings:
Base 6, Idle 4, Mid 0, WOT 1

I would've thought that this setup would be good for at least low 13's and with a bit of technique maybe dip my toe into 12's, but I was wrong. My first run was 14.5@95 whic is the same time I ran with stock everything, a 3" exhaust and boost creep. I tried everything to get into 13's. Adjusting the WOT on the MAFT, turning down the boost a notch, lowering fuel pressure because I might have been too rich. Nothing worked. It was a night of mid to low 14's and trap speeds between 95 and 97 mph. The only good thing that came out of this was that I was either up against bad cars or bad drivers. I took out a old style Mustang Cobra, a GTO, a Galant VR-4, a Prelude, and a SRT-4. It was all in the launch. I lost to one Mustang when I tried to launch in neutral, and the shop Evo from Diamond Star Motorsports.

Finally on my last run of the night, after getting tips on where to shift, (I was shifting at 6K, a few friends told me to run it to redline), I gave it one more go. I adjusted the stutterbox to 5K and lined up against a supercharged Cobra. When the hammer dropped, I launched like I've never launched before. Strange sounds came from the back end and I had visions of my poor 3-bolt making its way to that great Mitsubishi Graveyard in the sky. But she held on and made my way down the track. The Cobra caught up to me at mid track and roared past me. The final result? I scored a 13.98@95 versus his 13.52@104.

I'm happy that I got 13's but still, WTF is up with my trap speeds? I know this turbo is more than capable. I have one friend who ran 12.7 in his Galant. The guy I bought my turbo from was running 12.5's before he sold it to me. And they were using 550's. Anyway, here's a log of that last spectacular run, when I get the chance I'm going to run another boost leak and compression test.

Maft settings were Base: 6, Idle: 4, Mid: 0, WOT: 0
Base pressure set @ 43 psi.
Boost set to 18 psi.

TIMA  	O2-R  	TPS  	RPM  	KNCK  	INJP
27° 	0.10V 	100.0% 	3813 	0 	4.86ms This is the stutterbox engaged
31° 	0.08V 	100.0% 	4781 	0 	0.00ms
29° 	0.08V 	100.0% 	4781 	0 	0.00ms
28° 	0.06V 	100.0% 	4750 	0 	0.00ms
28° 	0.06V 	100.0% 	4875 	0 	7.68ms
27° 	0.06V 	100.0% 	4875 	0 	0.00ms
27° 	0.04V 	100.0% 	4906 	0 	0.00ms
27° 	0.04V 	100.0% 	5188 	1 	9.47ms  This is where I launched 
27° 	0.43V 	100.0% 	4281 	0 	11.78ms
18° 	0.45V 	100.0% 	4500 	0 	12.03ms
18° 	0.47V 	100.0% 	4344 	0 	13.06ms
18° 	0.49V 	100.0% 	4500 	0 	12.80ms
18° 	0.49V 	100.0% 	5281 	0 	14.08ms
22° 	0.51V 	100.0% 	6031 	1 	14.59ms
22° 	0.51V 	100.0% 	6656 	0 	15.10ms
19° 	0.53V 	100.0% 	7094 	0 	14.34ms
18° 	0.45V 	10.2% 	6750 	0 	0.00ms
45° 	0.27V 	100.0% 	6031 	0 	9.47ms
29° 	0.57V 	100.0% 	4375 	0 	12.54ms
18° 	0.59V 	100.0% 	4750 	0 	13.57ms
19° 	0.60V 	100.0% 	5031 	0 	14.08ms
20° 	0.60V 	100.0% 	5281 	0 	14.59ms
21° 	0.60V 	100.0% 	5625 	1 	15.36ms
21° 	0.62V 	100.0% 	5750 	1 	15.36ms
24° 	0.62V 	100.0% 	6000 	0 	15.62ms
23° 	0.64V 	100.0% 	6250 	0 	15.87ms
22° 	0.64V 	100.0% 	6375 	0 	15.62ms
21° 	0.64V 	100.0% 	6594 	0 	15.62ms
20° 	0.66V 	100.0% 	6906 	0 	15.10ms
19° 	0.66V 	100.0% 	7000 	0 	14.59ms
18° 	0.66V 	100.0% 	7125 	0 	14.34ms
18° 	0.49V 	10.2% 	6750 	0 	0.00ms
45° 	0.02V 	100.0% 	6344 	7 	8.19ms
26° 	0.70V 	100.0% 	4875 	13 	12.54ms
14° 	0.70V 	100.0% 	4969 	12 	14.85ms
15° 	0.72V 	100.0% 	5156 	12 	14.85ms
16° 	0.72V 	100.0% 	5250 	11 	15.10ms
17° 	0.72V 	100.0% 	5406 	11 	15.62ms
18° 	0.74V 	100.0% 	5500 	10 	15.87ms
18° 	0.74V 	100.0% 	5594 	10 	16.13ms
19° 	0.74V 	100.0% 	5719 	10 	15.87ms
19° 	0.76V 	100.0% 	5781 	10 	16.38ms
19° 	0.76V 	100.0% 	5938 	10 	16.13ms
20° 	0.76V 	100.0% 	6000 	9 	15.62ms
21° 	0.76V 	100.0% 	6063 	9 	15.87ms
21° 	0.76V 	100.0% 	6188 	9 	15.62ms
20° 	0.78V 	100.0% 	6281 	8 	15.87ms
19° 	0.78V 	100.0% 	6281 	8 	15.87ms
18° 	0.78V 	100.0% 	6406 	8 	15.87ms
17° 	0.78V 	100.0% 	6531 	8 	15.62ms
17° 	0.78V 	100.0% 	6531 	8 	15.62ms
17° 	0.78V 	100.0% 	6531 	7 	15.36ms
16° 	0.78V 	100.0% 	6781 	8 	15.62ms
16° 	0.80V 	100.0% 	6813 	8 	15.36ms
16° 	0.80V 	100.0% 	6875 	7 	14.85ms
16° 	0.80V 	100.0% 	6906 	8 	14.85ms
16° 	0.80V 	100.0% 	6938 	7 	15.10ms
15° 	0.80V 	100.0% 	7063 	7 	14.85ms
15° 	0.80V 	100.0% 	7156 	6 	14.59ms
16° 	0.80V 	48.2% 	7063 	6 	3.84ms
21° 	0.82V 	12.9% 	6688 	0 	6.14ms
34° 	0.80V 	100.0% 	5219 	19 	10.75ms
18° 	0.82V 	100.0% 	5281 	19 	13.82ms
14° 	0.84V 	100.0% 	5406 	18 	14.85ms
15° 	0.84V 	100.0% 	5438 	18 	15.36ms
15° 	0.84V 	100.0% 	5469 	17 	15.62ms
16° 	0.84V 	100.0% 	5563 	17 	15.87ms
16° 	0.84V 	100.0% 	5563 	17 	15.62ms
16° 	0.84V 	100.0% 	5625 	17 	16.13ms
16° 	0.84V 	100.0% 	5688 	17 	15.87ms

 

[DSMvroom]

could it be your 60' ?

im dont know for a fact but i was under the impresion that 2.1 is godly for a FWD and poor for AWD. I may be mistaken so please don't think I'm trying to put down your 60'

 

[CanadianTSi]

That MPH says your WAY down on power. Have you checked your compression lately?

 

[Quasimondo]

Compression was 135-135-110-135. The low compression on the #3 cylinder can't be enough to drop power that much, can it? It still wouldn't explain why my trap speeds are the same as when I was still on the 14B with a stock fuel system right down to a rewired pump and a 3" exhaust that gave me boost creep up to 23 psi.

It's not the launches that I'm having a problem with, btw. I was cutting 1.9's all night. I could do better, which brings up another point. That 14.5 run that I still have posted was with a 2.1 60-footer. I improve my launch and my trap speeds are still the same. WTF

 

[steve]

Compression was 135-135-110-135. The low compression on the #3 cylinder can't be enough to drop power that much, can it?

Minimum compression for a 1G 4G63 Turbo is 114psi. Max difference between high and low is 14 psi.
I get about 160 psi across the board. So your number aren't very hot and cyl 3 is shot.

Steve

 

[Quasimondo]

Minimum compression for a 1G 4G63 Turbo is 114psi with a max difference of 14 psi. I get about 160 psi across the board. So your number aren't very hot and cyl 3 is shot.

Steve

Definitely not what I wanted to hear

 

[CanadianTSi]

The fact that you gained no mph means that you gained no power, therefore your car has issue's.

 

[danl]

In my real world experience your compression numbers are fine. I’ve seen guys run 11’s with 80 psi across the board. Do a leakdown test as well to check for bent valves. A leakdown test is more important sometimes. I would start out by checking for boost leaks. Also your not knocking very much, you need to push the timing/boost/air/fuel ratio harder. What is your air/fuel ratio. It’s hard to tell but I’ve seen situations like yours where the car had some pretty bad boost leaks and was running extremely rich.

 

[Quasimondo]

I don't have a wideband so I don't know what my A/F ratio was when I made those runs. I will do a leakdown test and a boost leak test when I get the chance When I pulled the plugs they were fouled so I'd assume that the engine was running on the rich side of things. I know this engine is worn and hopefully that bum #3 cylinder is a head problem and not bad rings.

It might be an unrelated problem but when I pulled the plug wires to do the compression test, I noticed signs of arcing between the wires and the valve cover, or between the wires themselves. I didn't expect that since the wires are less than a year old when I ran I didn't experience any misfires, but better quality wires might be on my list of things to do list as well.

 

[boostcrazy92tsi]

your o2 volts r extremely low and your knock is high. your obviously running lean. but yea 110psi on a cylinder is bad news and truthfully the engine isnt lookin very well with your other cylinders. i would say its time for a rebuild. your timing is pulled in the higher gears too which is a loss of power. just my .02

 

[aero_sallee]

Sounds like some good ideas. I had a couple to throw out there. Next time you go to the track try turning the boost to 15-16 psi, or throwing in some race gas. Get rid of the knock and you would gain some good power.

 

[Quasimondo]

I tried that before, on my first run I was running rich:

TIMA   O2-R    TPS  	  RPM  	KNCK  NJP
19° 	0.23V 	100.0% 	2188 	0 	4.35ms [B]Stutterbox Engaged[/B]
28° 	0.14V 	100.0% 	3531 	0 	4.61ms
31° 	0.14V 	100.0% 	4813 	0 	5.89ms
29° 	0.10V 	100.0% 	4906 	0 	0.00ms
28° 	0.10V 	100.0% 	4906 	0 	0.00ms
27° 	0.10V 	100.0% 	4875 	0 	0.00ms
27° 	0.10V 	100.0% 	4719 	0 	0.00ms
27° 	0.10V 	100.0% 	4781 	0 	0.00ms
27° 	0.10V 	100.0% 	4844 	0 	8.45ms
27° 	0.10V 	100.0% 	4781 	0 	0.00ms
27° 	0.10V 	100.0% 	4875 	0 	0.00ms
26° 	0.10V 	100.0% 	4750 	0 	0.00ms
27° 	0.08V 	100.0% 	4875 	0 	8.19ms
27° 	0.08V 	100.0% 	4813 	0 	7.94ms
27° 	0.08V 	100.0% 	4906 	0 	0.00ms
26° 	0.10V 	100.0% 	4781 	0 	0.00ms
27° 	0.08V 	100.0% 	4719 	0 	0.00ms
26° 	0.08V 	100.0% 	4781 	0 	0.00ms
26° 	0.08V 	100.0% 	4813 	0 	8.19ms
27° 	0.08V 	100.0% 	4844 	0 	0.00ms
27° 	0.08V 	100.0% 	4969 	0 	0.00ms
26° 	0.10V 	100.0% 	4844 	0 	7.94ms
27° 	0.08V 	100.0% 	4750 	0 	0.00ms
27° 	0.08V 	100.0% 	4938 	0 	9.73ms
24° 	0.31V 	100.0% 	3719 	1 	10.24ms [B]Launch![/B]
18° 	0.33V 	100.0% 	4156 	1 	11.26ms
19° 	0.33V 	100.0% 	4094 	0 	11.78ms
18° 	0.35V 	100.0% 	4156 	0 	12.54ms
18° 	0.37V 	100.0% 	4875 	0 	14.34ms
19° 	0.39V 	100.0% 	5594 	0 	15.10ms
23° 	0.39V 	100.0% 	6031 	0 	15.36ms
23° 	0.41V 	100.0% 	6531 	0 	15.62ms
20° 	0.43V 	100.0% 	6969 	0 	15.10ms
18° 	0.35V 	10.2% 	6813 	0 	0.00ms
45° 	0.21V 	100.0% 	6250 	0 	6.66ms
33° 	0.47V 	100.0% 	4094 	0 	9.73ms
24° 	0.51V 	100.0% 	4500 	0 	11.52ms
19° 	0.53V 	100.0% 	4688 	0 	13.31ms
19° 	0.55V 	100.0% 	5000 	0 	14.59ms
19° 	0.57V 	100.0% 	5188 	0 	15.36ms
21° 	0.59V 	100.0% 	5469 	0 	15.87ms
22° 	0.60V 	100.0% 	5656 	0 	16.13ms
23° 	0.60V 	100.0% 	5875 	0 	15.87ms
24° 	0.62V 	100.0% 	6063 	0 	16.13ms
24° 	0.62V 	100.0% 	6219 	0 	16.13ms
22° 	0.64V 	100.0% 	6313 	0 	16.13ms
21° 	0.66V 	100.0% 	6625 	0 	15.87ms
20° 	0.66V 	10.6% 	6563 	0 	0.00ms
38° 	0.68V 	12.5% 	6250 	0 	0.00ms
32° 	0.62V 	100.0% 	4313 	0 	9.73ms
24° 	0.70V 	100.0% 	4531 	0 	12.03ms
18° 	0.72V 	100.0% 	4719 	0 	13.57ms
18° 	0.74V 	100.0% 	4813 	0 	14.85ms
19° 	0.74V 	100.0% 	4938 	0 	15.10ms
19° 	0.74V 	100.0% 	5031 	0 	15.36ms
19° 	0.76V 	100.0% 	5125 	0 	15.62ms
20° 	0.76V 	100.0% 	5281 	0 	15.87ms
21° 	0.76V 	100.0% 	5281 	0 	15.87ms
21° 	0.76V 	100.0% 	5375 	0 	15.87ms
21° 	0.78V 	100.0% 	5469 	0 	16.13ms
22° 	0.78V 	100.0% 	5656 	1 	16.64ms
22° 	0.78V 	100.0% 	5719 	1 	16.38ms
23° 	0.78V 	100.0% 	5719 	0 	16.38ms
23° 	0.80V 	100.0% 	5875 	1 	16.38ms
23° 	0.80V 	100.0% 	5969 	0 	16.38ms
24° 	0.80V 	100.0% 	5969 	0 	16.13ms
23° 	0.80V 	100.0% 	6094 	0 	16.13ms
23° 	0.80V 	100.0% 	6219 	0 	16.13ms
23° 	0.80V 	100.0% 	6313 	0 	15.87ms
22° 	0.82V 	100.0% 	6344 	0 	15.62ms
21° 	0.82V 	100.0% 	6438 	0 	15.87ms
21° 	0.82V 	100.0% 	6500 	1 	15.87ms
20° 	0.82V 	100.0% 	6500 	1 	16.13ms
20° 	0.82V 	100.0% 	6563 	0 	15.87ms
19° 	0.82V 	38.8% 	6656 	0 	0.00ms
35° 	0.82V 	10.2% 	6375 	0 	0.00ms
45° 	0.51V 	100.0% 	4906 	0 	9.47ms
25° 	0.84V 	100.0% 	5031 	0 	12.54ms
19° 	0.84V 	100.0% 	5063 	0 	14.08ms
20° 	0.86V 	100.0% 	5094 	0 	15.10ms
20° 	0.86V 	100.0% 	5156 	1 	15.36ms
20° 	0.86V 	100.0% 	5188 	0 	15.36ms
20° 	0.86V 	100.0% 	5250 	0 	15.62ms
21° 	0.86V 	100.0% 	5313 	0 	15.62ms
21° 	0.86V 	100.0% 	5313 	0 	15.87ms
21° 	0.86V 	100.0% 	5406 	0 	15.87ms
22° 	0.86V 	100.0% 	5438 	0 	15.87ms
22° 	0.86V 	100.0% 	5469 	0 	16.13ms
22° 	0.86V 	100.0% 	5469 	0 	16.13ms
22° 	0.86V 	100.0% 	5594 	0 	16.38ms
22° 	0.86V 	100.0% 	5656 	1 	16.38ms
21° 	0.86V 	100.0% 	5625 	1 	16.13ms

I ran 14.3 @ 96

I'm going to do a leakdown test, hopefully that #3 cylinder is salvageable and it's a problem with the head and not the bottom end. 135 isn't the best compression numbers, but if I can get that cylinder up to the rest maybe I can hold off on a bottom end rebuild for another year.

 

[pneumo]

If you haven't done it yet, get some new plugs and wires. The arcing you saw on the old wires will cause misfires, tho you might not notice it during a run. Misfires will also give you false low O2 volt readings since it reads oxygen content. You could be running rich and not know it.

When you get the wires, also pick up some of those plastic wire separator things. Use them to keep each wire from touching anything. Dont let the wires touch each other, and don't let them touch the metal valvecover. This will prevent any arcing.

And while you're in there it's not a bad idea to clean the coil pack. Just a regular wipedown will work.

 

[Goodguy162000]

Ouch! 135? 110? I have only one word: Rebuild

 

[4pistons]

Are you still running the stock 1G BOV? Here's what happened to me:

My car would pull hard at first and then seem to fall flat and lose power. I managed a 13.90 at 100 mph last year (In 90* heat) but it wouldn't pull hard on the top end.

One day it started to run rough at idle and when I got into the boost, at around 12 psi, I heard this loud, continuous, "screaching" noise. I'd never heard it before so at first it scared me that something major was wrong. What happened was my BOV air bypass tube came off (so I was basically venting to atmosphere) My darn BOV was leaking around 12 psi even though I could get it to boost to 18+. I must have really been overworking that 14B and heating the hell out of the air. No wonder I get a lot of knock. I carefully crushed the valve and took it for a test ride. Same thing, no effect!

There's a small hole on the under side of the BOV that is exposed to upper intake pipe boost that connects to the underside of the diaphragm and enables the BOV to be "fast acting." But it also allows boost to help PUSH the diaphragm open and lift the valve. I needed something to help keep it closed until I let off the throttle. I did a little research and found a mod that eliminates that passageway to the UIP and directs it to the atmosphere where there is no pressure to lift the valve. http://www.thedodgegarage.com/turbo_bov_mod.html I didn't install the vent tube, just left the hole.

I bolted it all back together, including the bypass tube and went for a ride. Holy Crap!! It pulled like a freight train!! And when I let off the gas I could plainly hear the SH-SH-SH-sh-sh-sh of the valve operating that I could never hear before. The difference is friggen amazing even at 16 psi. Now I'm using every pound of boost instead of venting it. This is how it should have been running all these years! I wish that bypass tube had come off sooner!

Try disconnecting your bypass tube to test for BOV leakage and see if you don't have the same problem. BTW - I've leak tested my intake system a dozen times to 20+ psi in the past 5 years and this problem never showed. I don't know why.

Rick - '91 GSX

 

[speedlogik]

AWD=faster e.ts, slower trap speed

 

[Quasimondo]

It was the engine. Leakdown tests confirmed bad rings and a blown head gasket, possibly in more than one place. I'm already planning on rebuilding, should have it back up and running sometime this summer.

 

[4GSixty3]

In my real world experience your compression numbers are fine. I’ve seen guys run 11’s with 80 psi across the board.

Not to get off topic but I figured I would point something out. I have always been told that anything below 100psi, the car will not start. When I cooked my headgasket, compression was like 85-95 in all cylinders and I had to hook jumper wires up to the car and keep cranking it until it started. Damn junkyard dicks wouldn't let me keep it there, OUT OF THE WAY, for 1 night so it could be towed the next day ! How did they keep the car running long enough to make passes down the track? Jumper cables?

 

[wishihadatalon]

Hmm I have been having the same probs with almost the same setup. 13.5 at 97mph. Cant figure it out. On cold days it pulls really hard and at night its better. I put 4 car lengths on a car that trapped at 99mph in the matter of 2 gears. Brand new motor and rebuilt head so I don't know what mine can be other than the side mount and the stupid rfl bov leaking. I am putting a fmic on this weekend with a crushed 1g bov. Hope that goes well. Also a new tuning device to hopefully get this car in check. It previously ran a 13.5 with a 2.1+ 60ft with the old driver and I was cutting 1.8 and on my 13.5 run I managed a 1.7 60ft.