LNF New Parameters

[oldskool]

Thanks gmtech, that does help - that is essentially the reveiw and info I was looking for. I've seen some of your discussions on cam tables as they relate to response and cruising economy, but I'm not ready to take the hit on mpg yet if there are other ways to sharpen up the response. FWIW, my DAL table is not much different than stock right now - the minor changes from stock are only in the 90-100% load columns. So, I'm sure there is plenty of room to adjust the lower load columns to tweak throttle response.

The situation I'm trying to adjust is the one where the car is cruising along in the range of say 2500-3000 rpm at low throttle (<<50%). Then you punch it. There is a very noticable lapse between the pedal hitting the floor and the car taking off. Everybody with an LNF has seen it, everybody's felt it. It irritates me that a car primed to be one of the most responsive turbocharged cars ever, with direct injection, variable cam timing, and a perfectly suited turbo for low end response, ends up being limited by a 1-second lag in the throttle plate opening when going from low ETC% to WOT.

For comparison, my other car used to be an M62 supercharged 2.2L eco sunfire. If you put that car in the same situation (light throttle at 2500 rpm, then punch it), the instant push put a smile on my face everytime, even though ultimately the car was not that fast (213whp at it's best). I'm not expecting that kind of "response" out of the solstice, but there has to be some improvement to be made over how it is now. I'm taking tomorrow to do some work on it, and the LE5 TB is on the list. Based on your review, I think it is a step in the right direction.

[gmtech16450yz]

Couple quick thoughts...

We have two cars with almost identical hp and torque, my Sky and my wife's CTS-V wagon. The wagon is a beast. Floor it at any speed and it will slam your head against the headrest. I floored it at 70mph once and knocked my wife's sunglasses off her head and into the back seat!

The Sky is fast, but not like that. It's a 2.0L turbo for heavens sake! I don't care what the throttle is doing, it's still a turbo and it's not gonna hit like a supercharged engine, no matter what the size. Guess which car is faster 60-100? The Sky (mostly because of the weight difference obviously). Drive 10 people in both cars and 9 of them are gonna swear the Caddy would blow the Sky away. It just "feels" like a top fuel dragster.

Another thing to think about and try...
When you're cruising along at 60mph, go from closed throttle to half throttle and take it up to 80mph. Do the same thing except go from closed throttle to full throttle. Look at the elapsed time differences, I'm betting you'll see they're very close. If you're at 2500 or 3000 rpm, the engine in no way needs the throttle full open to make whatever power it's capable of at that particular rpm. I've seen plenty of engines make LESS power or accelerate SLOWER when you go full throttle at low rpm as apposed to going only half throttle and then flooring it once rpm's come up. Pretty smart of those engineers that worked on our Bosch computer and software huh? The throttle "lag" everyone hates is probably doing more GOOD than harm. The guys that put together the stock ECM and programming were no dummies.

Remember, there's a computer controlling all the engine settings like fuel, ign timing, cam timing, etc, etc. Look at your timing tables and you'll see keeping the air loads and throttle positions lower at low rpm's will put you in much better timing cells than if you tell it you've got your foot to the floor.

On the cam timing/mpg thing, the timing tables I put up here over a year ago are not even close to what I use now. (I should take them down but it's kinda funny when I see so called "professional" tuners using those exact tables in their tunes! Those tables are no where near the best settings. lol.) It is possible to have better throttle response AND retain mpg with cam timing changes. Don't be afraid to just try something and see what it does to the mpg. Even if you lose a little mpg's, you might figure it's worth it.

[oldskool]

I do appreciate the feedback, and i know that the LNF will never feel like any roots supercharged car, but i really do think there is room for improvement. I've been in cable driven throttle body cars with small-ish turbos and the response is much better. That is interesting on the CTS-V vs the sky though lol.

We'll see what the LE5 TB and some additional tuning does. Like I said, i'm sure there will be some noticeable improvement. If not, oh well, live and learn.

[sstupid]

Couple quick thoughts...

We have two cars with almost identical hp and torque, my Sky and my wife's CTS-V wagon. The wagon is a beast. Floor it at any speed and it will slam your head against the headrest. I floored it at 70mph once and knocked my wife's sunglasses off her head and into the back seat!

The Sky is fast, but not like that. It's a 2.0L turbo for heavens sake! I don't care what the throttle is doing, it's still a turbo and it's not gonna hit like a supercharged engine, no matter what the size. Guess which car is faster 60-100? The Sky (mostly because of the weight difference obviously). Drive 10 people in both cars and 9 of them are gonna swear the Caddy would blow the Sky away. It just "feels" like a top fuel dragster.

Another thing to think about and try...
When you're cruising along at 60mph, go from closed throttle to half throttle and take it up to 80mph. Do the same thing except go from closed throttle to full throttle. Look at the elapsed time differences, I'm betting you'll see they're very close. If you're at 2500 or 3000 rpm, the engine in no way needs the throttle full open to make whatever power it's capable of at that particular rpm. I've seen plenty of engines make LESS power or accelerate SLOWER when you go full throttle at low rpm as apposed to going only half throttle and then flooring it once rpm's come up. Pretty smart of those engineers that worked on our Bosch computer and software huh? The throttle "lag" everyone hates is probably doing more GOOD than harm. The guys that put together the stock ECM and programming were no dummies.

Remember, there's a computer controlling all the engine settings like fuel, ign timing, cam timing, etc, etc. Look at your timing tables and you'll see keeping the air loads and throttle positions lower at low rpm's will put you in much better timing cells than if you tell it you've got your foot to the floor.

On the cam timing/mpg thing, the timing tables I put up here over a year ago are not even close to what I use now. (I should take them down but it's kinda funny when I see so called "professional" tuners using those exact tables in their tunes! Those tables are no where near the best settings. lol.) It is possible to have better throttle response AND retain mpg with cam timing changes. Don't be afraid to just try something and see what it does to the mpg. Even if you lose a little mpg's, you might figure it's worth it.

My tuner was always asking me why I would always ease into the throttle in 2nd gear. I swear it goes faster that way.

[Breadfan]

My tuner was always asking me why I would always ease into the throttle in 2nd gear. I swear it goes faster that way.

I'm going to have to agree. Roll-on throttle rocks on an LNF. Jabbing the throttle results in a lag feeling instead of a rollercoaster feeling. I don't care though. I like it for what it is. I want a daily driver that rocks when I need it. For timing, I'm at the beginning of the timing table learning curve, but I hope to reinvent the wheel, so to speak, so I can understand it rather than just cribbing someone elses tables.

[|V3nom|]

soooo....how about some layering so we can run two tunes at once?!

i love the way trifecta has that option but apparently vince isnt the best tuner so im not getting the full potential out of my car that i can...

[articzap]

Dual tunes on a switch would be the best but I doubt they will take time to figure it out.

[cobaltssoverbooster]

It has to go through the bcm and Chris has already stated they are only working on PCM parameters for now

[|V3nom|]

never hurts to ask.