Pekka_Perkeles

I had my car dynoed yesterday and, well, it went lean right after 4500 rpm and end-result was more or less melted plugs. See pic below. So what would you do? Take heads off to see if pistons are ok and if some metal debris from plugs are melted into piston so that it would glow and eventually break the whole piston?

The combination I have is as follows: forged 427, cnc'd Edelbrock LS2 heads, LS6 intake manifold, 228/232 cam, 1 7/8 Kooks headers, dual fuel pumps (original C5 Z06 2003 pump and additional Bosch 420 pump both running all the time), 60 lbs injectors and Vortech T-trim supercharger. The fuel pressure remained around 60-61 psi during the dyno runs and boost was around 11 psi I think.

Could it be that because of rather small injectors (60#) I'm running out of fuel and because of that the torque goes rapidly down after 4500 rpm? The dyno pull below is the first one and the only one that we managed to run up to around 6300 rpm. When we tried again, AFR went rapidly up right after 4500 so we of course stopped the runs (I think AFR went around 14-15 from 11.5 so no wonder why plugs melted).

I changed new plugs and the engine runs now ok, no strange mechanical noises or anything like that, but of course I don't use rpm's over 4000 and I'm quite scary if the pistons are ok or not.



The torque is Newton-meters but by dividing numbers with 1.36 you'll get ft-lbs so for example the maximum torque was 894 Nm @4500 which is about 657 ft-lbs from the rear wheels.

Here are the scary spark plugs:

Websy21

iTrader: (34)

Yikes man, something is obviously wrong there. What kind of plugs, tr6's? Hard to tell in pics but I think thats what they are.

Pekka_Perkeles

Yep, these are NGK TR6's.

I did not gapped them to 0.035 but used them as delivered.

Jimmy P

iTrader: (177)

Who is doing the tuning on it? How much timing, and what type of gas was used? I think the 60lbs should be plenty of injector for your setup.

Pekka_Perkeles

Tuning is done in Europe. Gas is equivalent to U.S. 93 octane I think. Timing I have to check, I don't recall what it was. IAT's were around 140 fahrenheit in first pull and in later pulls around 170 f.

Pekka_Perkeles

I just checked the HP Tuners logs by myself and they look very strange (but I'm not tuning expert).

The AFR goes to 12.5 when the dyno pull start and I guess it's already way too high. Advance is around 20. AFR stays flat until 4500 when it goes quickly to 15! At the same time advance is around 16..15. Then rpm's go down a bit, as well as AFR and then they go higher again...but it's full throttle all the time. At 5500 rpm AFR is again high, 13.5 and timing is about 11 degrees.

Below are two pics of same pull. I'm starting to think that the tune is way off... damn, where could I find another tuning expert? There aren't many in Europe...

tollway bandit 1

iTrader: (2)

Why on earth did you stay in it at 15to1, were you not watching the air/fuel?

Pekka_Perkeles

Well, I too really wonder why my tuner did not stop the dyno run but instead pushed it all the way. I was in a different room during dyno pulls and saw the logs today just moments ago.

I guess it's time to try to find another tuner. But meanwhile, should I take the heads off to see if there's any damage? Any opinions?

Haans249

iTrader: (24)

You don't have to pull the heads, do a leak down test and that will tell if there is something wrong. Sounds like you're ok though... but best to check with a leakdown test. Its really hard to tell what is going on without the actual tune file and log file. There is not much to tell from the pictures of the log you posted, other than what you stated.

Pekka_Perkeles

Here are the HPT logs. I will post the tune file later today.

Black X

iTrader: (9)

Couple things I notice from a quick glance... Your not logging a 2 or 3 bar map sensor. the Map value maxes out at 104 because it wont log any higher. This does nothing for us because we cant see how much boost it was making.

Second... FIRE YOUR TUNER... anyone who stays in the throttle at 15:1 air fuel under boost should be shot.


It doesnt look good in the log bud, I hope you can find someone better before it costs you a motor.

Jimmy P

iTrader: (177)

I 100% agree with the above posts, get a different tuner.

SRZ

iTrader: (14)

Where in Europe are you? May be able to assist if you are in Germany.

y2khawk

iTrader: (5)

Just a quick glance at the screen shots, the fuel after the MAF maxes is not being added fast enough.

MAF pegs at 481, AF goes lean. Bad.

What MAF is on the car? and why has the MAF table not be extended to 512 g/s? It will buy you some room, but eventually that's all you get.

You will either need to address adding fuel quicker with the PE table, or move to a 2 or 3 BAR OS and ditch the MAF completely.

Pekka_Perkeles

My MAF is from stock C5 Z06 LS6 engine, i.e. it is 85 mm GM MAF.

I just ordered set of LS7 head gaskets and I'm planning to remove the heads during weekend to see if pistons, combustion chambers and valves are ok. I guess by pushing valves a bit I could see if there are any problems with the seat surface.

I did drive the car something like 150 miles after dyno pulls and all was perfect, and I need to drive another 250 miles before I'll get the car into proper garage to remove the heads. This may be overkill, but I just want to be sure that there aren't any signs of cracks or holes or anything unusual. I don't have compression test tool, though.

I also ordered new 2 bar MAP sensor today so I will install it during the weekend as well. It would be nice to know if I can drive the car with new 2 bar MAP without any tuning? I mean that I may need to drive the car to another country to get a proper tune and that would mean driving with new MAP (and with existing MAF of course). Furthermore, I guess I would need a new intake temperature sensor as isn't it so that it is now integrated into existing 85 mm MAF?

ls1290

iTrader: (20)

I would whip the tuner with a C5 hood performance seal until he leans how to tune. Has the person ever worked on fuel injected cars before, let alone a LS1?

Keith

Frans96SS

iTrader: (15)

Deff FIRE your tuner.... hes TERRIBLE.... If their are no other tuners in europe let me know if you would posisbly want me to fly out.

Pekka_Perkeles

Here's the HPT tune file.

I'm trying to get, sorry, will get another person to tune my car. Luckily there's one who could do it in a neighbour country. How do I know he's good? Well, because he has proven his tuning capabilities with his own street car pushing more than 800 rwhp with LS-based engine and big F1 Procharger. If he can't do it, then I'll find someone else.

Anyway, before that I need to look the pistons. I will post some pics during the weekend. Hopefully they look nice. Otherwise I need to order some new Manley forged pistons...

Frans96SS

iTrader: (15)

instead of pulling off the heads you could get a bore scope and look inside the cylinder..

Photochop

iTrader: (74)

Yeah, I know what I'd do, KICK YOUR TUNER IN THE ***

Then pack up your stuff and head to a reputable shop you can trust. Thats very unfortunate man, I hope the bottom end survived it.