Did you verify that at WOT the TB blades are fully open, and exactly horizontal?

 

Fred I dont know who you're directing that to but yes I have verified mine are wide open, thats one of the first things I checked. Seen that too many times on carbed hot rods.

 

To the OP (wrd1972). Several pages later and I can't remember if he checked that.

 

Yes we checked that at the tuners.

I am now sending the logs to WS6. Maybe he can post them. I want that 400 RWHP if at all possible by resolving this problem w/o going LS1 lid.

 

This should work.

http://www.mediafire.com/file/1mmm45...st1_no_CAI.uni

http://www.mediafire.com/file/jdvzti...rty_filter.uni

 

Everbody with datamaster please check em out and comment. All help is greatly appreciated.

 

If you dont mind email me a copy of the tune you're using as well. I am going to go out on a limb here and guess that in the pe vs rpm table up top goes negative a fair amount to get the air fuel ratio right. Spark advance looks a little much to me at 41 degress up top but you're the ones who had it on the rollers and if it works it works.

The bad news is it doesnt seem that your removal of the cai improved your vacuum issue although your airflow values do appear higher during some of the spikes. Which i'm not entirely sure I would trust since the airflow increases in a pretty linear fashion and then just jumps as it approaches 300g/sec then it just kind of does its own thing after that with pretty big swings.

 

The tuner jacked with timing and fuel for about an hour and a half to optimize the tune. He found that the motor wanted more fuel this go around compared to a year ago. Main differences between then and now are bigger injectors, .030" less lift on the cam lobes and LT headers. By and large the motor did not significantly respond to changes in either fuel or timing.

At work now. I will send the tune when i get home.
Thanks

 

Your tuner is pretty good from what I see here, I assume you went for a 12.7 a/f ratio on the dyno.

I was right about one thing though your maf table 4 has been jacked with pretty hard right after the 9808hz cell which is in the 330 range. It differs from mine and from a stock one to the tune of about 40 g/sec all the way to the end of the table. That is probably the cause of some fluctuation in air fuel ratio up top, might mention it to him idk he probably had his reasons for doing it. Just makes for some uglyness on the log graph, and I highly doubt the airflow hopped around 70g/sec up high like on one of the logs. He may have done it to aid shift recovery or who knows what, I usually take care of that in the rpm pe tables since its cleaner and assures it is applied where it is needed rather than based on airflow.

Alright enough thread hijacking.

 

I am confident he did have his reasons for jacking the MAF the way he did. Bluecat has an incredible reputation for knowing how to optimize LT1 and LS1 motors. He will sit down and tweak on a tune no matter how long it takes just like it was hs own personal car.

I cant speak to the MAF settings, its over my head. What are your thoughts after seeing the file and tune that maybe a 58mm TB might help resolve my problem some? How did you determine he went for 12.7 A/F?

 

Without the dyno or a wideband at the very least its kind of hard to do anything because you dont have anything to go by. By the numbers all you need to do is change cells in the pe vs coolant table that are 16 to 14.2. That would put your commanded air fuel ratio at 12.9 by the numbers. I would play it on the side of caution leaning things out with no verification and maybe go half of that change, its up to you, your motor your money.

The 58mm tb as you know is not a bolt on deal the bores in the intake are not quite that large and some grinding is required. If certainly probably wont hurt. Depends on how much cash you can get out of your current tb if I would do it or not. If I was doing the job the intake would be coming off to do the cutting, some do it with it on the car, that doesnt fly as far as i'm concerned.

I changed too much stuff the next time I went into my engine and I have changed a ton of stuff since so i dont really have a good a/b/a comparison. People tend to say big tb's are a waste, i've never seen any of the 'big dogs' run a stock tb and several of them sport a monoblade.

 

Intake is already bored for 58mm TB. LE did it so in this case it is plug and play. Right now everybody is out of the professional products 58mm TB. When they get them back in stock, I plan to get one.

 

Here are my findings.


Final thoughts.
Looks like the 90 degree elbow is a good size restriction and the MAF is NOT of any concern. The 58mm flows a little better for my motor compared to the 52mm TB.

 

interesting info

 

id go with a lid. Im putting a slp lid, FTRA and Mallory ign on soon and taking before and after dyno numbers. Interested in the results.