Low LSA = Hard to tune?
This is a discussion on Low LSA = Hard to tune? within the Computer & Tuning forums, part of the LSx Technical Help Section category; I've been shopping for a "near" future cam buy, and I want a nice and choppy idle, but from what ...
02-11-2008, 05:25 PM #1
Low LSA = Hard to tune?
I've been shopping for a "near" future cam buy, and I want a nice and choppy idle, but from what I've been reading lately, people say it really hard to tune. I'm looking at a custom grind TSP 228r range, with a 112 or 111.5 lsa, and stock ported heads (until I can afford aftermarket). My car is M6 and not a DD.
What makes a lower lsa so hard to tune? Is it that you lose too much vaccum, or that its just hard to match the valve overlap with the a/f ratio? I'm just curious as to what the real reason is? Thx!
02-11-2008, 08:06 PM #2
you get more overlap with the lower lsa making part throttle driving more finicky. I'm sure Frost will chime in here and add his input. Who do you have tuning the car? A 228r on a 112 for an M6 should'nt be a big deal at all for a tuner than knows what they're doing.
02-12-2008, 02:17 AM #3
228 112lsa on an M6 won't be a problem for your tuner. If it's you tuning and it's your first, it could be more challenging, especially finding the balance of airflow between idle and it's offset at cruise. That low RPM overlap can fool your O2s in closed loop operation as you get fresh air escaping through into the exhaust which your sensors read as a false lean and attempt to correct.
02-12-2008, 08:05 AM #4
- Join Date
- Mar 2007
83 Z28 new project
- 98 Formula WS7-sold:(
what about the same cam or a bit bigger, only in an a4
02-12-2008, 09:00 AM #5
I have the 228R on a 114 in my a4. It idles fine and part throttle isn't to bad either. Keep in mind I tuned it and someone that actual knows what they're doing would have my car running much better than I do. It still runs fine though.
02-12-2008, 09:01 AM #6
02-12-2008, 06:01 PM #7
Thanks for clearing this up for me. Again though, are there any vaccum issues when going to a lower lsa, or is it nothing to worry about unless you go radically low (like 106lsa or something like that)?
02-12-2008, 06:43 PM #8
I think that if you kept it on a 112 you'd be much better off in the long run. Everyone has their own opinions but for me personally I wouldn't go lower than that. Can you go lower and have a driveable car......sure. I would spend some time talking to Frost and I'm sure he can help you out quite a bit. My experience is a pimple on a knats ass compared to the number of cars and setups he's tuned.
02-12-2008, 09:55 PM #9
It's not even so much that it is hard to tune, it just takes more time to get right in a wide range of conditions. I'm pretty picky about how they drive.
02-13-2008, 04:17 AM #10
02-13-2008, 09:47 AM #11
- Join Date
- Jul 2006
- Glen Carbon, IL
- 2000 Camaro SS
I'm pretty picky about how mine drives as well. I had Keith Mccord tune mine and I hate it. I have tuning software and have made some tweeks only to flash it back to what KM did. I am not very good, but WOT is easy to tune. I am sure he will make it right, but I haven't had time to log any driving to email it to him b/c of the weather.
I have a TSP 231/237 on a 112 LSA and had to set converter lockup at 55 mph to stop the annoying bucking. Warm startup idle sucks and it won't stay running. Cold starup idle is fine.
02-13-2008, 03:47 PM #12
Well, I don't really need logs if your issues are specific. If you are tuning with HPT, send me your file to Steve@lsxtune.com and describe your problems being as detailed as you can with regard to things like engien temp, rpm, how you are driving when something happens; etc and I will see if I can help you out.
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