Does your boost drop on a hot day?
#3
Registered User
Join Date: Feb 2004
Location: columbia md.
Posts: 1,041
Likes: 0
Received 0 Likes
on
0 Posts
The density difference of air at 90F and 40F is approx. 10% less. Less air results in less compression or boost pressure...2.5psi Boost difference might suggest a leak...???
Last edited by jpc350z; 08-04-2006 at 09:01 AM.
#5
Registered User
iTrader: (2)
Join Date: Nov 2003
Location: Riverside, California
Posts: 507
Likes: 0
Received 0 Likes
on
0 Posts
Springs don't know what the difference in temperature is. They open with force applied to them. A 9 pound spring opens at that same pressure in 50 or 90-degrees. Unless the spring is suffering from heat fatigue then it should always read the same PSI.
#6
New Member
iTrader: (51)
Originally Posted by Beer Goggles
Springs don't know what the difference in temperature is. They open with force applied to them. A 9 pound spring opens at that same pressure in 50 or 90-degrees. Unless the spring is suffering from heat fatigue then it should always read the same PSI.
JET
#7
New Member
iTrader: (18)
BUT, not everybody runs off spring pressure, i for one dont, and my boost drops too on hotter days, and temp does affect air intake temps and density, boost should be a little lower on hot days. thats why you need to pay close attention to your boost gauge if your car is tuned for hotter temps and then it gets real cold, your boost will rise. on cold days turn the boost controller down.
Trending Topics
#8
Thanks guys..
I'm going to get the electronic boost controller soon. The stock one is just too unstable. Today is pretty hot again and I punched it and got 10.8psi.. Off topic, but is it just me or the APS fuel pumps gets louder as the car gets warmer? Last night I drove around quite of bit all day, and the fuel pump started to buzz pretty loud.. I thought it was going to blow up or something...
I'm going to get the electronic boost controller soon. The stock one is just too unstable. Today is pretty hot again and I punched it and got 10.8psi.. Off topic, but is it just me or the APS fuel pumps gets louder as the car gets warmer? Last night I drove around quite of bit all day, and the fuel pump started to buzz pretty loud.. I thought it was going to blow up or something...
#10
Registered User
iTrader: (2)
Join Date: Nov 2003
Location: Riverside, California
Posts: 507
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by tig488
BUT, not everybody runs off spring pressure, i for one dont, and my boost drops too on hotter days, and temp does affect air intake temps and density, boost should be a little lower on hot days. thats why you need to pay close attention to your boost gauge if your car is tuned for hotter temps and then it gets real cold, your boost will rise. on cold days turn the boost controller down.
What you're saying is partially true. Air is more dense on cold days, but to reach a certain pound per square inch the same force has to be applied. If you're using a boost controller that opens the wastegates at a certain RPM, then yes you will get most boost, but like most people we run the stock wastegates which use a spring. And if you sit on that spring in the winter or the summer you weight the same. I don't weigh more in the winter that the summer. But think about what you're doing. You're forcing air iinto a set amount of space, and a spring is holding the door closed. Once the set pressure is applied the spring opens. The spring doesn't know it took longer and more air to reach 9psi.
IF you're turning up boost on hot days (I wouldn't recommend that with hot unstable air and 91 oct) you're compensating for the less oxygen per unit volume, not how much pressure.
#12
Registered User
iTrader: (3)
Join Date: Jul 2004
Location: St. Pete, Fl
Posts: 252
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by leeboyNY
Thanks guys..
I'm going to get the electronic boost controller soon. The stock one is just too unstable. Today is pretty hot again and I punched it and got 10.8psi.. Off topic, but is it just me or the APS fuel pumps gets louder as the car gets warmer? Last night I drove around quite of bit all day, and the fuel pump started to buzz pretty loud.. I thought it was going to blow up or something...
I'm going to get the electronic boost controller soon. The stock one is just too unstable. Today is pretty hot again and I punched it and got 10.8psi.. Off topic, but is it just me or the APS fuel pumps gets louder as the car gets warmer? Last night I drove around quite of bit all day, and the fuel pump started to buzz pretty loud.. I thought it was going to blow up or something...
#14
Originally Posted by beastie
I see you have the APS ST. I'm surprised you only have that little of a drop in boost, no matter what the temp.
#15
Registered User
iTrader: (3)
Join Date: Jul 2004
Location: St. Pete, Fl
Posts: 252
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by leeboyNY
Haha~ Funny~ I read so much stuff about the boost drop, I put a custom dual exhaust with 3" pipes, so I have a very small boost drop. Zeitronix datalogger showed 1psi boost drop from 11.4 to 10.5psi. Only problem is it's freaking loud!!!!!!!!!
#16
Registered User
iTrader: (3)
Join Date: Jul 2004
Location: St. Pete, Fl
Posts: 252
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by leeboyNY
Haha~ Funny~ I read so much stuff about the boost drop, I put a custom dual exhaust with 3" pipes, so I have a very small boost drop. Zeitronix datalogger showed 1psi boost drop from 11.4 to 10.5psi. Only problem is it's freaking loud!!!!!!!!!
#17
Registered User
Join Date: Dec 2004
Location: Melbourne
Posts: 110
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by leeboyNY
Well, it's kind of an obvious question, but I don't know by how much? It's pretty hot today.. 90F... Mine went from 11psi to 8.5psi.. Or is there something wrong? Thanks
#18
Originally Posted by beastie
If you don't mind, what did that custom exhaust cost ya? Did you use a custome reverse Y pipe or buy one made already?
Thread
Thread Starter
Forum
Replies
Last Post
Lt_Ballzacki
Brakes & Suspension
39
08-06-2021 06:19 AM
Colombo
Forced Induction
35
11-09-2020 10:27 AM