alex722607

iTrader: (3)

Quick question for everyone that can answer this. I swapped in a 5.3 with an LS1-F intake and all the bells and whistles associated with it earlier this year, which I wrote about in a build thread.

My question is this: the car is my daily driver and has been since March, I have put over 3000 miles on it and probably closer to 4000. I am running a mail order tune from the LT1swap website. It runs fine, but the swap depleted my funds for getting a tune and things have been coming up ever since. If I continue to run it on the mail order tune, will it harm the motor, other than causing my fuel mileage to suck?

Don't get me wrong, I fully intend to get a tune, but I am in college right now, so its kind of difficult to put the funds aside to get a tune.

cosmick

No, and you can't blame the canned tune for your MPG, either. That's a function of your driving style, unless you geared it something insane like a 4.56:1 axle with no OD, or worse yet, something like a 2.73:1 axle with a T56 that has a 0.50:1 sixth.
The L36-swapped '83 RX-7 I just built is running a canned tune from LT1Swap.com, he did ask my trans and axle ratios and rear tire size before doing my tune, MPG is very good, 37 hwy ( 0.72:1 x 2.29:1 on 225/60R15 rears )
If your MPG is an electronic failure, then it's probably an O2 sensor

alex722607

iTrader: (3)

Well I've been driving it like a grandma this past week and I still only get 18-20. I have changed 02 sensors twice thinking that was the problem. I also replaced the stock lm7 cam with one from a 99 ls1 from an f-body when I was building it.
Gears are 3.27, stock gearing in the 4l60e

customblackbird

iTrader: (15)

18-20 seems pretty normal if its city and highway combined. You should see high 20s on the highway I would think. Its still a V8. What stall are you running?

Also how much did you guys pay for the tune from LT1 swap? Im in the process of swapping a 5.3LS in my bird with a 2004R with a .67:1 highway gear, billet 2400stall lockup converter and 3.55 rear gears. I was going 1700-1900rpms at 70-80mph with 28" tall tires and a 521 BBF.

I'm going to be boosting my 5.3LS with 10-12psi and going with HP tuners probably but curious about how much the tunes cost.

alex722607

iTrader: (3)

I dont know what converter I have, it came with the trans when I got a rebuilt unit from a company in Virginia. I do know that I do 2000 rpm's at 62-70 mph. I also drive mostly highway, so I think it should be better than 18 driving like a grandma

WTR388

He did my ECM, stock LS1/T56, stock rear so a 3:08?
I get near 30MPG if I'm nice on the highway, I turn like 1400rpm at 75mph or so.

I did have an O2 sensor out at first, I got better mileage after I fixed that... I've been beating on it pretty much for 5000km this summer, hasn't had any issue. I feel it's running a bit rich due to the look of my exhaust tips, but I'm happy.

alex722607

iTrader: (3)

So maybe it's my stall speed. If im doin 2000 rpm at 62-70 and ur doin 1400 at 75 (yea I know you have a manual, but still).

customblackbird

iTrader: (15)

What did u guys pay for the tunes?

My lightly modded 2014 ram crew cab with the 5.7 hemis I can average 18-21highway usually and that's a 6500lb truck moving at 70mph or so and its not very aerodynamic. Hence why I think mid to high 20s with a 5.3 and a light aerodynamic 3rd gen.

customblackbird

iTrader: (15)

Yea your Rpms seem high. I don't feel like ur converter is locking up. Can u feel it lockup? Should be noticeable and the car should feel like a manual like direct power when u give it alittle gas. That should drop your Rpms like 300-400rpms.

alex722607

iTrader: (3)

I think I payed 70 for my base tune, which is what i am running. I can feel the converter locking up. Could the tune have anything to do with it, or do you think it is specificaly converter related?

alex722607

iTrader: (3)

I know that at 100 mph, my RPM's are at 4000 I believe

customblackbird

iTrader: (15)

$70 isn't bad but I don't think he can tune a different operating system for that price I would need to convert my MAF system to a 2 bar speed density operating system.

Something isn't right with ur combo. Can you shift the trans manually to verify its going into each gear? I'm thinking u either have a 4th gear clutch problem or lockup issues. The 3rd gear is a 1:1 Ratio and with my 3.55 gears in 3rd I was around 3k at 55-60mph which is hard to tell with converter stall.

alex722607

iTrader: (3)

Oh, yeah I actually drove it manual mode today, as follows:

1st - 0- 9/10 mph
2nd - 10-20 mph
3rd - ~25 - 40 ish
4th - 42+

I will have to look at what she tachs at when I shift her, gonna have to do that tomorrow, and I am gonna have to verify those speeds as well, cause I gave a ballpark

I know that I asked for a stock trans for an 02 T/A with an LS1, but i have no idea what gears are in there, there have been so many 4L60E's that perhaps they just reassembled it with whatever. Except that doesn't make sense because they are a performance trans shop - so I dunno.

I could inquire, but I got the trans in January so its been a while, unless they build every single one with the same gears, or if they wrote it down somewhere, then I doubt they would remember what the stuck in there, is there another way for me to tell??

I have 3.27 gears in my 9-bolt, but I accidentally told the mail order tuner that I had 3.23's, would that make any difference - cause I doubt it? Then again I don't really get the gearing part at all.