Engine Performance This section is for discussion on all engine building related questions.
Sponsored by:
Sponsored by: KPower

Forged pistons & turbo lag reduction

Thread Tools
 
Search this Thread
 
Old 09-12-2014, 01:12 PM
  #41  
Senior Member
iTrader: (5)
 
bcrx7's Avatar
 
Join Date: Jul 2005
Posts: 697
Total Cats: 53
Default

Originally Posted by concealer404
Well if you were waiting for boost, wouldn't that actually be a threshold issue, not lag?
This is at like 6000rpm, they are pretty odd!
bcrx7 is offline  
Old 09-12-2014, 01:32 PM
  #42  
Elite Member
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 10,917
Total Cats: 2,201
Default

Originally Posted by Leafy
No for realz, 70's turbo cars, well above the boost threshold, its kind of like punch it and pray that in a couple seconds (well it feels like a couple seconds) when the turbo actually spins up that you're straight enough that it doesnt snap sideways.


I know this... i was making fun of the maybe intentional omission of "full" before boost.

You guys ruin everything.
concealer404 is offline  
Old 09-12-2014, 01:37 PM
  #43  
Elite Member
iTrader: (1)
 
Leafy's Avatar
 
Join Date: Jun 2012
Location: NH
Posts: 9,479
Total Cats: 104
Default

oh.
Leafy is offline  
Old 09-12-2014, 04:26 PM
  #44  
Junior Member
 
guttedmiata's Avatar
 
Join Date: Sep 2012
Posts: 440
Total Cats: 3
Default

Originally Posted by bcrx7
You get on the throttle mid corner hoping by the time you are hitting the exit you have boost!
Which is exactly what we had to do with the greddy setup on the 1.6 when we got the car. After changing the intake piping and the entire exhaust from the head back to dumping right after the drivers seat, we only had to floor 2/3 of the way through the corner. Still sucked. It's fixed now though.
guttedmiata is offline  
Old 09-12-2014, 04:37 PM
  #45  
Senior Member
iTrader: (5)
 
bcrx7's Avatar
 
Join Date: Jul 2005
Posts: 697
Total Cats: 53
Default

Originally Posted by guttedmiata
Which is exactly what we had to do with the greddy setup on the 1.6 when we got the car. After changing the intake piping and the entire exhaust from the head back to dumping right after the drivers seat, we only had to floor 2/3 of the way through the corner. Still sucked. It's fixed now though.
Yes, the wrong size turbo or issues with the system will cause lag. The main reason for the diesels lag as I mentioned. Most diesels will get more power/torque and most likely better fuel milage just upgrading exhaust to a bigger/free-flowing system. Not sure what the restrictions are that makes the car makers put crappy systems on. Most likely noise.
bcrx7 is offline  
Old 09-12-2014, 05:16 PM
  #46  
Junior Member
 
guttedmiata's Avatar
 
Join Date: Sep 2012
Posts: 440
Total Cats: 3
Default

Had massive free flowing exhaust on my truck. Laaaaaaaaaged anyway. Unless I could brake to build boost, I would always loose the jump or hole shot........and then smile as I powered past my competitor.
guttedmiata is offline  
Old 09-12-2014, 06:43 PM
  #47  
Senior Member
iTrader: (2)
 
Twodoor's Avatar
 
Join Date: Mar 2014
Location: Meridian, Mississippi
Posts: 628
Total Cats: 44
Default

Originally Posted by thenuge26
Haha I bet it is crazy, especially compared to the fiesta I'm DDing now, as the NYT writer said the gears are so far apart they need counseling.
I'm going to be at Cozzolino Motorsports (SE Indianapolis) around noon Saturday to dyno the car. Need to make sure I am not running too much boost My goal at this point is to make the most power I can while not going more than around 230 to 240 torque at the wheels. According to "virtual dyno" I am there... but I need a real dynojet to back that up before I trust it.

Keith

PS: Dynoing in 5th just seams weird!
Twodoor is offline  
Old 09-13-2014, 12:04 AM
  #48  
Senior Member
iTrader: (5)
 
bcrx7's Avatar
 
Join Date: Jul 2005
Posts: 697
Total Cats: 53
Default

Originally Posted by guttedmiata
Had massive free flowing exhaust on my truck. Laaaaaaaaaged anyway. Unless I could brake to build boost, I would always loose the jump or hole shot........and then smile as I powered past my competitor.
This is off the line?
bcrx7 is offline  
Old 09-13-2014, 08:55 AM
  #49  
Junior Member
 
guttedmiata's Avatar
 
Join Date: Sep 2012
Posts: 440
Total Cats: 3
Default

Originally Posted by bcrx7
This is off the line?
Or from a roll. Which was lag.
guttedmiata is offline  
Old 09-13-2014, 12:24 PM
  #50  
Senior Member
iTrader: (5)
 
bcrx7's Avatar
 
Join Date: Jul 2005
Posts: 697
Total Cats: 53
Default

boost threshold hahaha
bcrx7 is offline  
Old 09-13-2014, 02:28 PM
  #51  
Moderator
iTrader: (12)
 
sixshooter's Avatar
 
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 20,652
Total Cats: 3,011
Default

Some of the old Chrysler K-cars were really unresponsive with their old T3 turbos. A buddy had a little convertible that you could stomp the throttle and have time to say "wait for it" before it would make power and torque steer you towards the ditch!
sixshooter is offline  
Old 09-13-2014, 05:03 PM
  #52  
Senior Member
iTrader: (5)
 
bcrx7's Avatar
 
Join Date: Jul 2005
Posts: 697
Total Cats: 53
Default

Well at least the K-cars you could disconnect the wastegate and make some few infinite-PSI runs down the track! K-vans are nice sleepers haha
bcrx7 is offline  
Old 09-13-2014, 07:04 PM
  #53  
Senior Member
iTrader: (2)
 
Twodoor's Avatar
 
Join Date: Mar 2014
Location: Meridian, Mississippi
Posts: 628
Total Cats: 44
Default

Originally Posted by thenuge26
Even concealer's gt2554 car has lag. We measured it on the datalog, it was like .25 seconds
Having taken a ride in Ben's car this inspired me to do a highway data log for lag documentation. On my GT2860R doing a steady 80 mph on the highway in 6th gear (about 4300 RPM, well above boost threshold) from going WOT to boost hitting 9.5 psi was .366 seconds, (this is where my wastegate starts to open) and another 3.44 seconds to hit set pressure of 11.5 psi at .73 seconds after going WOT... but that is relying on boost creep to get from 9.5 psi to 11.5 psi.

I will have dyno sheets up in my build thread soon, just have to re-size and post them Then it is off to the 1/4 mile track Sunday.

Keith
Twodoor is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Full_Tilt_Boogie
Build Threads
84
04-12-2021 04:21 PM
stoves
Suspension, Brakes, Drivetrain
5
04-21-2016 03:00 PM
Rick02R
WTB
3
01-03-2016 07:18 PM
cale saurage
DIY Turbo Discussion
16
10-01-2015 11:25 AM



Quick Reply: Forged pistons & turbo lag reduction



All times are GMT -4. The time now is 09:01 AM.