BadLtBlu99TA

iTrader: (9)

Why does it seem like my 402stroker motor runs better at night time then it does during the day time in the heat ?? it seems like it kinda hesitate and runs on 7 cylenders during the day time , and at night it runs Great as soon as it gets about 75 degrees or so , i've checked all my Spark plug wires or what not they are all connected i dont know whats going on ..

1.8t

Coolant temp/IAT table in your tune more than likely. That and the fact that cooler air is more dense and will just plain make more power.

Sharpe

iTrader: (7)

I don't know, but you better figure it out. Call whoever built and/or installed your engine.

BadLtBlu99TA

iTrader: (9)

THanks man my coolant temp runs i think around 190 , but below the 210 mark , so yeah i'll probally have to get it fine tuned still .

WS6R6

iTrader: (1)

Everything runs faster at night. But it shouldn't feel like it runs like crap in the daytime, you should just get better times. Get it checked out with the builder/tuner!

BadLtBlu99TA

iTrader: (9)

see i got the engine from TSP , but the Tune was a CPU tune which i knows now right and all i have on the engine is maybe 100 miles i know i need a tune i was just making sure its possibly a IAT table might be off ..


i just wish there was some way i could be running cooler air into the intake

LS1-NAVY

iTrader: (1)

^^boost/nawzzz

WKMCD

iTrader: (2)

The cooler the air the more dense it it. Don't make it too complicated.

99blancoSS

iTrader: (115)

^^^ simple as that, cooler air makes more power. What compression are you running?

mike c.

iTrader: (1)

???????? every motor runs better in cooler weather. My last set up in 80-85deg weather I would run 11.3's.@122 When I would go back to the track in late october I would run 11.1's@125. On my new 402ci I ran 10.86@128,can't wait to see what the cooler weather in oct will do.

1.8t

Guys, I believe everyone knows(hopefully??) that cooler air makes more power and that the car will run faster during the evening than the day. However, there have been people like me that have had drastic performance reductions in the heat. I could have said, "well its hot, so it should be slower" but the fact of the matter is that the car was losing way too much power for an increase in 15 to 20deg. In 80deg weather my car was only trapping 120.xmph. To me, that was absolutely ridiculous for the power I am making.

So, I called up my tuner and he noted the IAT timing table. This table can pull 3deg at 86deg IAT's if it has been left stock. It only climbs the higher your IAT is and most cases depending on your intake, the car can run perfectly fine with it zero'ed out at some of the lower values. We attacked this table and then I went back to the track. The DA was +1625' and the car trapped 124.13mph. Thats more like it. This winter should bring 126~127mph, which is right where this car should be IMO

DrkPhx

iTrader: (15)

What was the DA when you trapped 120mph? 15-20 degrees change in ambient temperature is a big difference when racing. Barometric perssure, humidity (which, imo has the most impact) and track tremp have to be taken in consideration.

Keep in mind the LS1 f-body IAT spark tables are no where near as aggressive as the Gen IV ECM's. The stock IAT tables on my TB SS pulls 4 degrees (in all values) at WOT at 86 degrees compared 0 degrees in the same table and temp in the stock 98 PCM.

1.8t

The DA's were +2350' and +2870' the 2 times I went to the track when it was trapping 120.xmph. To be fair, the car also never was cooled down during those previous 2 visits. Coolant temps were always 195+ at the beginning of the run. The trip to the track where it trapped 124.13mph, coolant temps were 175deg at the time of the run. Cooler coolant temps on this car have routinely(even when I just had bolt ons) given me 1~1.5mph. On the dyno, the car picks up 10whp/wtq from 205deg coolant temps to 180's. So it would appear it was a combination of a better DA, a proper cool down period, and a retuned IAT table.

White_Hawk

iTrader: (3)

How much do you know about the tune? Is it speed density or just open loop? Try to get more tune info. It won't be as strong during the day, but it shouldn't sound like it is running on 7 either.

-Geoff

99blancoSS

iTrader: (115)

You need to look at all the variables not just one. Have you tried recording some data while your running slower? Might help to figure out whats going on if you have some data to work with. What compression are you running? IF your running 12:1 and are having issues in the heat only; I wonder what that could be.... maybe detonation? and the knock sensors are doing their job? Wild guess but the low octane timing table will slow the car down quite a bit.

BadLtBlu99TA

iTrader: (9)

I figured the Stock ls2 spark plug wires were broke cause it seems like its not running on all 8 now .. its screwed up , so i got some MSD 8.5mm Spark plug wires plugged them all in , and the car still dont seem like its running right , go im wondering if my IAT table is off , cause right now its only 79 degrees out and it still dont seem to run right ... could knock Sensors or 02 sensors cause this ?? i changed out my 2 02 sensors and its still doin g the same .. i need help here someone ... i think im gunna go get a dyno tune but i dont wanna dyno tune it when it only seems like its running on 7 cylenders ..

BadLtBlu99TA

iTrader: (9)

SOmetimes when i get on the Gas it seems like its kinda Chugging out of the exhaust , the exhaust dont sound smooth at all so im confused ..

BadLtBlu99TA

iTrader: (9)

My compression Ratio is 11.3:1

99blancoSS

iTrader: (115)

Do you have any software you can monitor with? Compare how it runs at night and in the day but you need data.

1.8t

Sounds like more than an IAT table issue. Sounds like a tune issue in general and or possible sensor failure. You need to post your tune in the PCM/Diagnostics section and go from there.