My combo. 427 truck block bored .060. Half filled. Studded mains with pro-gram billet caps. Callies 4.375 stroke billet crank with sbc rod journals. BME aluminum rods 6.600 long. Diamond pistons custom design .300 crown a typical ring package for longevity. Ceramic coated tops Teflon coated skirts. .220 tool steel wristpin. 1st version of the motor will have a set of stock oval port heads that I ported with 2.200 intake valves and 1.800 exhaust. Test port flowed [email protected] lift. Those heads are mated with the 230/224 cam. Gonna try out the Pro-filer sniper intake if I have the chance otherwise it will be a dart oval port piece. Gonna wait till it's actually together to worry about a carb. Headers are going to be 2 inch primary unequal length with 3 inch collectors. Hoping for 1200-1400 with the stock heads. When money permits I'll be switching to trick flow 320cc heads that will be opened up to around 340cc and hopefully flow around 430-440. A bigger cam in the 260/250 range Those heads will have the sniper intake on them. That's the combo I hope might make 2000 hp.

 

Hey 35spline, any updates?

 

Well the new cam arrived last week while I was on vacation. I hope to get to work on it next weekend.

 

You really have not ruled out tuning here at all. Gkring can help you with this too. In my opinion and Gkring can relate, your AF ratios need to be much leaner from idle to 3500 to 4000 rpms. I think you are not getting hot enough exhaust gases to spin the turbos. You should have no problem running 13.5 or so up to 3000 rpms and start scaling the fuel table richer from there. Gradually I would go to 12.0s up to 4000 and past that 11.5 or richer if needed which I doubt.

I would not mess with the timing until you get the AF table sorted out. Even if the motor likes 38 degrees that will just be icing on the cake after the AF ratios are right.

You definitely have exhaust housing that are too big. Get yourself a set of .81 housings and I bet that motor will wake up a lot.

If you can post up an AF map. That will tell what is going on.

 

Here is the target AF table

 

The scaling for rpms and boost are pretty rough. I would try the rpm cells starting at 500, increase each cell by 500 rpms. I would reduce the number of cells showing vacuum on the left side of that map. Leave the 12.03, leave the 6.51, make the next cell down 0, then add 1 psi to each cell after that going down.
You are definitely running rich. Change the AF tables to 14 in the cells from -12.03 down to 0.52 across to 600o rpms. You wont hurt it.

From 1 to 5 psi I would try 13 to 1
From 5 psi to 8 12 to 1
From 8 psi to 10 on up run 11.5
Above 10 psi 11 psi to be safe.

With the low timing you are running you are not going to hurt the motor but you should definitely feel and see a difference. There is probably a scaling function you can use after you input all of these new numbers. Use it. It will smooth out all of the numbers and the ECM wont have to make major pulsewidth changes from one cell to another. Meaning the motor wont buck like a horse. Highlight the whole screen and have the computer rescale the values in the cells.

I do have another concern. Your VE table might be out of whack too. Can you post up a copy of that too?

And by the way, is this motor running on pump gas? I was not sure.

 

Something like this?

 

Looks good.

How about the VE table and what type of fuel are you running on the motor?

 

I am tuning on 93 gas with the option to switching to E85 down the road. Here is the VE table, notice that the scale bar does not reflect the change I made to the AF table. In fact those changes were not kept when I saved the file. I will have to get some help tuning the tables.

 

You can dial in the VE tables once you have the AF ratios right.

You should be able to log a run and then adjust the VE tables to match.

 

Let us know if those changes help.

 

OK, The new cam is in and also switched from batch fire to sequential fire. Only got a little time in tuning so nothing to report on turbo spool up. There is some hesitation when accelerating from idle right now. Needs tuning. The smaller cam makes a huge difference in idle quality, very smooth and quiet. BTW the new cam has the 4 and 7 swap in firing order. It will probably be at least a week before I will be able to report any significant updates.

 

Is that VE table supposed to be set to Lambda ?
It looks upside down to me and way off at that.

 

Looks like its not in % like most FI computers. .1 to 1.25.

 

I got to drive the car this afternoon and had mixed results. The data logs showed boosted interval was lowered about 500 RPM (3 psi at 2800 and 8psi at 4000) but there was a serious spark issue starting around 4000 RPM (big time backfire). Did not have time to look for the problem. Maybe the crank sensor?

 

Look over in the builds section for a 71 nova twin turbo 540. That is my friend Shannon's car that I built the engine for and we just ran on drag week. 555 with ProFiler 320 heads ( out of the box they flow ~ 360btw and I did some mild porting to get them to ~390). The cam is a Comp solid roller 266/268 on a 114 with ~.740/.714 lift installed at 110 with a pair of MP 76 turbos. On the trans brake we had to launch at 3000 because by 3500 it would be at 15psi boost. There is nothing too big about your cam. Sure the profile was way wrong but it should still have been building boost. I'm surprised with a stick you can get the car to hold traction at the desired 25-3000rpm. Must have a helluva suspension.

 

It is a 3 link with the anti squat is dialed in around %50

 

revolutionary

Do you have the specks on the MP turbos? AR? turbine trim?

 

I pulled the motor out last Sat due to an abnormal engine vibration (in and out of gear) that starts at 2000 RPM goes away and returns around 4000 RPM. Going to get it re-balanced.