5.3 turbo lag
10-03-2016, 10:04 AM
#1
5.3 turbo lag I had this s480 96 1.32ar t6 speced for my stock bottom lq4 i was running at first. The 6.0 did really well with this turbo. Now i have a 5.3 behind it. It doesnt go positive till around 3600rpm. Laggy for sure.
My question is what can we change to help this situation? 76mm borg? Or diferent exhaust housing?
Setup is a 05 5.3 cam only. 224/230 114 cam. True divided 2.5" hotside with 4" downpipe.
I do all my own tuning and im at 10psi now without any vaccum connected to wastegate. Basicly double spring pressure from 5psi standard. With a jgs50mm.
Last thing i cant even really do a burn out unless i build boost up to do it. Is this typical? All tm is removed and pe is not delayed.
Running a 4l80e, with circle d 3400 converter, and 3.73 gear on 28" tire. Thanks guys.
My question is what can we change to help this situation? 76mm borg? Or diferent exhaust housing?
Setup is a 05 5.3 cam only. 224/230 114 cam. True divided 2.5" hotside with 4" downpipe.
I do all my own tuning and im at 10psi now without any vaccum connected to wastegate. Basicly double spring pressure from 5psi standard. With a jgs50mm.
Last thing i cant even really do a burn out unless i build boost up to do it. Is this typical? All tm is removed and pe is not delayed.
Running a 4l80e, with circle d 3400 converter, and 3.73 gear on 28" tire. Thanks guys.
10-03-2016, 05:30 PM
#4
If you have a twin scroll turbine housing, you can merge your exhaust before the turbine housing (yes all 8 cylinders must merge into 1 tube) and then build a quick spool valve to block off 1 side of the turbine housing. Or buy an off the shelf quick spool valve if you can make it fit. I built my own years ago on my 500whp 3.0 V6 turbo...It SIGNIFICANTLY reduced spool time and made way more torque down low. Success and well worth the time to get it all working correctly.
10-03-2016, 08:41 PM
#5
I would just sell this billet wheel 80 before trying all that. Main problem is not being able to do a burnout. Cant even turn over the tires to get hot enough to hold boost or hook. I done throwed around 32 degrees in it until boost. Im at 14degrees total with water meth and 10psi. I think i could add some timing in boost for sure. But that doesnt help make power out of boost. Thoughts?
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10-04-2016, 05:29 AM
#8
First off what do you mean you don't have vacuum on the gate? Are you saying you are just running the reference signal off the compressor housing or you don't have any pressure signal going to the gate at all?
The housing would make a bigger difference than the gears, as far as a burnout is concerned with any way, as would tapering down the exhaust side, but experimenting is the only way to know what is going to work best.
Gear for your RPM/MPH & go from there. I personally have never ran anything deeper than 3.55's in a v-8 turbo application... But I suspect there is maybe more than one thing throwing your response off.
Let me ask you this: What does your shift recovery look like? What kind of RPM drop do you see from each gear?
Also, you mention it doesn't start making positive manifold pressure until 3,600rpm, but what kind of time & rpm does it take to get to 10psi? A good set-up will usually see a few hundred RPM, & a second or so before being at only 10psi once it starts making boost. My last stang would start making boost about the same rpm as you see but it was a fraction of a second & it would hit 7psi then another fraction of a second it would be at 13psi, all in by 4,200rpm. I ran 3.27's & 27" tires on that car, but I only had ~6,400 rpm to play with & it would trap 140... So it worked perfectly.
Others can chime in but that cam may be a tad on the larger side... & degreed properly is a must.
The housing would make a bigger difference than the gears, as far as a burnout is concerned with any way, as would tapering down the exhaust side, but experimenting is the only way to know what is going to work best.
Gear for your RPM/MPH & go from there. I personally have never ran anything deeper than 3.55's in a v-8 turbo application... But I suspect there is maybe more than one thing throwing your response off.
Let me ask you this: What does your shift recovery look like? What kind of RPM drop do you see from each gear?
Also, you mention it doesn't start making positive manifold pressure until 3,600rpm, but what kind of time & rpm does it take to get to 10psi? A good set-up will usually see a few hundred RPM, & a second or so before being at only 10psi once it starts making boost. My last stang would start making boost about the same rpm as you see but it was a fraction of a second & it would hit 7psi then another fraction of a second it would be at 13psi, all in by 4,200rpm. I ran 3.27's & 27" tires on that car, but I only had ~6,400 rpm to play with & it would trap 140... So it worked perfectly.
Others can chime in but that cam may be a tad on the larger side... & degreed properly is a must.
Last edited by gtfoxy; 10-04-2016 at 05:38 AM.
10-04-2016, 06:45 AM
#9
If its any help, my s475/83mm/t4/1.1 doesnt go positive until about 3400 with either a 5.3 or a 6.0, with or w/o cams. In fact I ran a "turbo" cam and it went positive about 100 rpm later lol!. I have 2.125 hot pipes fully divided all the way. Sounds like I should of saved big bucks and went with the 1.32/T6 version and ran one gate and ended up with near the same results.
10-04-2016, 07:57 AM
#10
FWIW I'm running a 65/76mm 0.81 on my 5.3 fully wrapped 2.25" hot side and I am beginning to build positive pressure around the same rpm as you with 3.73 gears...my hotside doesn't have the smoothest transitions in the world but once it starts going positive it jump right up to 8-9 psi i have it set up at...Cant comment on burnout since i have a line lock and stick shift so i can rev it up and burn them, but i have no problem doing it off boost NA in second gear
10-04-2016, 09:14 AM
#11
When boost comes in its in quick within a second for sure. Like i said the 6.0 was way more responsive and was in boost sooner.
When i say i dont have vaccum reference i mean im doubling the gates spring rate by not hooking anything to it. No lines or vaccum to gate. Gate come with internal 5 psi spring which is what i make on boost with it hooked up.
When i say i dont have vaccum reference i mean im doubling the gates spring rate by not hooking anything to it. No lines or vaccum to gate. Gate come with internal 5 psi spring which is what i make on boost with it hooked up.
10-04-2016, 09:50 AM
#14
What intake?
What ECU? Any boost building options? (2-step, timing control etc?)
Do you have a line lock to do your burnout? Or are you trying to push thru your rear brakes?
2.5” hot side hurting you for sure. 2” is plenty for most 5.3’s.
That cam is too large for a 5.3 at low rpm
Not a good converter for racing IMO
Since none of that is cheap/easy to change… a 60-80 shot of nitrous for 1-2 seconds does wonders and is probably the cheapest and easiest option. Bottle lasts forever if you only spray for 1-2 seconds. Cheaper than farting around with converters and turbo housings, boost controllers, etc… and works better.
What ECU? Any boost building options? (2-step, timing control etc?)
Do you have a line lock to do your burnout? Or are you trying to push thru your rear brakes?
2.5” hot side hurting you for sure. 2” is plenty for most 5.3’s.
That cam is too large for a 5.3 at low rpm
Not a good converter for racing IMO
Since none of that is cheap/easy to change… a 60-80 shot of nitrous for 1-2 seconds does wonders and is probably the cheapest and easiest option. Bottle lasts forever if you only spray for 1-2 seconds. Cheaper than farting around with converters and turbo housings, boost controllers, etc… and works better.
10-04-2016, 12:54 PM
#16
I had a similar situation with a tight PTC converter setup for my 370” engine. Threw a 4.8 in to finish the season. Would barely make a pound on the brake, when I released the brake it fell on its face. Hit it with a 60 dry shot on the brake pre-turbo. Set to activate at 3200 and shut off at 3700. Made boost instantly. Once lit, engine made boost on its own easy.
My 4.8 would spin the tires with a line lock out of boost though. That's weird. Was on an ls1 intake, JFR 212/212 @ 112 cam .56x lift.
My 4.8 would spin the tires with a line lock out of boost though. That's weird. Was on an ls1 intake, JFR 212/212 @ 112 cam .56x lift.
10-04-2016, 01:11 PM
#19
Might see what it's spitting out for cranking compression. The trip 12 was great. Had mine 1.5* advanced and it was an animal in my 10:1 5.3.
Make sure to degree the cam, esp. on the gen4 5.3's they can be off quite a ways. My crank keyway was 8* retarded dot to dot. Was a whole new animal 1.5* advanced from the cam card. Spit out 200ish for cranking compression. Was very responsive. Picked up almost 12mph at the same boost level after I degree'd it!
My new 06 5.3 degree'd correctly dot to dot though (and so have many others) so not all have an issue. Always good to check anyway...
PTC or Yank seem to be the big contenders on budget turbo LS stuff. I've never ran a 4l80e though. I'd call up PTC and describe your combo to Dusty, he will spec something.
Make sure to degree the cam, esp. on the gen4 5.3's they can be off quite a ways. My crank keyway was 8* retarded dot to dot. Was a whole new animal 1.5* advanced from the cam card. Spit out 200ish for cranking compression. Was very responsive. Picked up almost 12mph at the same boost level after I degree'd it!
My new 06 5.3 degree'd correctly dot to dot though (and so have many others) so not all have an issue. Always good to check anyway... PTC or Yank seem to be the big contenders on budget turbo LS stuff. I've never ran a 4l80e though. I'd call up PTC and describe your combo to Dusty, he will spec something.
Last edited by Forcefed86; 10-04-2016 at 01:18 PM.