breecher_7

I have found that the YSI actually solves all problems but broken driveline parts... Its a great blower.

69ls6

what's the cam spec

Milan

Same cam as you....

BLOWNBLUEZ06

That was just a thrust bearing issue right?
I would pull all plugs and document compression and leakdown. Hopefully you have a benchmark. I've learned these relatively new stainless rings the companies are pushing wont put up with much before they quit on you.
After that, start tearing it down and get us some pics.

Turbo-Geist

Sorry to hear. It sounds like everything was in order.

From your post, it sounds like you were logging. Did you log 20 psi before you ever hit 5500 rpm? What is the actual spark timing on the log? Do you have any IAT or other spark adders that would have allowed timing to go above 13 deg with 42deg iat readings? How does everything else look from the log? Any airflow or injector bobbles?

What block is this?

Sorry for all the questions, just trying to understand the situation and see if I can provide any help.

Milan

Logged psi was 18.X. I have HP tuners set up to calculate boost based on barometric pressure so I can see if there is any belt slip and at what RPM we are building what boost. Boost gauge showed 20ish but keep in mind we are at altitude and that was from me glancing over at it.

Actual spark timing was 12.5* - 13*. There is nothing that would allow it to increase the timing. Only too high of IATs or ECTs could pull timing but not at normal operating range.

Everything else from the log looks good, boost increased steady with RPM, etc.

The injectors are brand new Bosch 127's....probably don't even have 100 miles on them yet.

Stock LS1 block from 99...which is likely the culprit if everything you guys have been saying is true. Edit: We aren't sure what pistons and rods are in there

This was the very first pull we tried with the smaller pulley. Prior to that we had the tune completed for the 3.2" pulley and made probably 20-30 3rd/4th gear pulls with the old pulley and no issued.

Turbo-Geist

Full tank of gas? E85 (E70 to E90) or 93 octane? Was the gas fresh or a few months old?

Filter on the Ysi or filterless?

Logged A/F was 10.58:1 (93) or 7.02 (E85) ?

Commanding 0.72 lambda or logged 0.72 lambda?

user_name

You don't have any idea what is in the motor but hit 20psi. Mystery should be solved soon. I'm sure ring gap and all kinds of things weren't ideal for making 900rwhp. Doubt a 99 ls1 block is really the issue.

Milan

Fresh 91 octane, no 93 at this high of elevation.

I don't tune with air fuel ratios, I use lambda only. .78 commanded lambda, I fattened the VE table on purpose because I wanted the car to be safe since I wasn't sure how it would respond to the 2.75" pulley. The reason we took the car out was to dial in the VE.

Stock A&A dongle with filter.

Car was built around forced induction, it came with a forged bottom end, small cam, ported 241 heads, A&A kit with a v3 Si trim blower, AEM meth injection, built diff and built tranny....silly me for thinking it could take 900 whp

user_name

Just saying 900rwhp is quite a bit. Not knowing what the clearances are, what ring gap is set to, rods, or especially compression I wouldn't be too surprised if it let go unless I found it was all done right once torn apart.

My own 347 has some awfully cheap parts in it, but everything about it is known, and it was spec'd for a power adder.

Turbo-Geist

Good info, Milan. I didn't realize that you only had 91 octane up there. Doe anyone know if they blend ethanol into 91 octane also?

Is the car using 100% methanol on the dual nozzle kit?

Also, you mentioned 0.78 lambda was commanded. Did you get 0.78 lambda on the log?

Y2KRoadster

Car is using dual meth 10 and 15 nozzles and it is 100%. Milan will have to chime in on the logs and I believe the gas up here is 10% ethanol.

Milan

Car was tuned to .78 lambda on the bigger pulley, for the pulley swap I took the VE table and added ~5% more fuel in boost just to be safe since I didn't know how it would react with the 2.75 pulley....it's just how I tune, I prefer to pull fuel out then run lean and have to add it in.

Gas up here is in fact 10% ethanol.

Also unless you are in a retarded state like California, octane almost always goes by elevation. 93 at sea level and 91 at higher altitudes.

Turbo-Geist

I guess they are still using winter blend up there? I checked the DA and it looks like the air was really good last night for Boise.

The winter blends are more oxygenated and have a lower stoich value. I like to run at no higher than 0.75 lambda when between 2 to 2.5 bar manifold pressure and using 93 octane. I usually like to go even a little richer and then find the sweet spot.

I missed it earlier in the thread, but it looks like you went from a 3.2" pulley to a 2.75" pulley. Would this be an increase of about 4 psi? Was the car making about 750 or 800 rwhp on the 16 psi setup? If so, I would guess that the pulley swap would be worth around a 10% power increase.

I think you said the timing advance was 13 degrees total. Was it 13 degrees at peak torque also?

Milan

Didn't make it to the dyno...this was literally the first attempt at WOT after the pulley swap...no clue what peak torque is because we didn't redline it so I don't have the whole fuel curve.

I'd say at least 5 more psi. As far as tuning goes...I'm the opposite, there is no reason for running richer than .75 lambda ever but that's just my opinion and a separate discussion completely.

Anyway....enough about the tune, obviously the car has much bigger problems.

Turbo-Geist

Good enough. After this I won't ask anymore questions. I'm just trying to learn. What are you inputting in the tune for lambda?

Thanks for all the info and good luck on finding out what's going on with the engine. I hope it's nothing major. Keep us posted.

Milan

I convert it to EQ ratio...1/.78 = 1.282

Turbo-Geist

Sorry, I meant what are you plugging in for the stoich value in the tune? Stock, 14.6, 14.3?

Milan

14.13

4DRUSH

Pull the heads & take close up pics of cylinder walls with digital camera (all angles) that works better than naked eye.