I'm thinking of getting my turbo em1 retuned in 3-4 weeks. in that time the weather will be in the low 50s. was wondering if i get it tuned, will it have an affect on the tune in the summer?
should i just wait n get it retune in the spring/summer?
i kind of want to have it done, cuz in the spring i won't have time.

oh, and the car will be stored in winter.

99 em1,s300,e85

 

Depends on how hot it gets in the summer ... Usually a summer tune is slightly conservative compared to the winter because of the intake air temps but most people have no real problems for low power builds

 

Make sure u drain the E85 and run pump gas for a good half hour before you store the car. the e85 will clog up the injectors if you let it sit for a while. Happened to 3 of my friends cars.

 

will it run right if i used pump gas since it's tune on e85?
i've parked in the garage for past 2 years w/o draining it. and it's fine but i also started and let runs for 30 min twice a week.

 

It'll run like pig rich if you put pump gas in a car tuned for e85.

As long as you keep cycling the fuel like that twice a week you'll be fine. 5 minutes would be good enough. I think it's better to keep the fuel system wet at all times. Free oxygen is not friends with anything in a fuel system.

E85 vaporizes slower below 50*F, so it can significantly change a tune. I won't tune if the ambient air is below 35*F.
E85 also affects blow-by rate because of oil dilution, and that rate can change your tune depending on fuel temp, pistons, and oil type.

More than likely you'll need some touch-ups next season if you live in a northern state or a high altitude.

 

so, it shouldn't affect the tune too much if i have retuned above 35*f. i know for sure it won't be below 35*f. prob around 50s. mn/wi weather toward the end of october.

 

Once a tune is locked in at any given temp, then it is just a compensation tables game. ECT, and IAT's are what you should pay special attention to. Be mindful of your Air/Fuel and Intake temps at tune time, then just adjust the values in the compensation tables to match the A/F's as the weather warms up.

I'm tuning my own car right now in the reverse order you are. (tuned it in the summer, now I'm cleaning up the high load IAT comps for colder, denser air). IAT comps can be a little bewildering at first, but once you understand how air density changes with temp, and how denser air affects your A/F, you're good to go.

 

^ generally yes, but if you tune below 35* the IAT will not compensate correctly. I assume it has something to do with frozen water in the air causing inconsistent combustion patterns or a malfunction with the O2, but it happened to me quite a few times before I figured it out.
On the other hand, it is easier to tune the IAT table if you have cold air to start with.
There's a section in the manual in my signature on tuning temp scales if you're curious.

 

ok, this has been bugging me for a while now. when i bought the car 2 years ago, the owner said when he got it tuned, the iat was not plugged into anything. it just hangs in the engine bay. that's how it was tuned and he said it runs and pull good. afrs are right on at idle,crusing, wot, etc
between him and me, it's been over 4 years now, and like i said i want to get it retuned since i updated some parts to it. like intercooler, new ic piping, bov, wg, manifold(from inline pro ss to now topmount) full 3" exhaust,gt35 from pte sc5031.
also, once the car is warm up or driving for a little bit, it idles kind of lean like...15-17 afr. but steady at 14.5-15.5 when cruising and wot at 11.5-8.

now, i'm torn whether to hook up the iat to ic pipe before tb or just to leave it?

 

Just hook it up ... When u get it tuned and temp changes the iat will help with compensating for it

 

Trust me, A/F will fluctuate with the change of the seasons/outside air temps. It's not a good idea to leave it unhooked. Hook it back up, and adjust IAT values to suit.

I live in Utah. There is no water in the air here. Frozen or otherwise.