Turbo Experts: Please chime in!
11-23-2018, 02:43 PM
#1
Pro
Thread Starter
Turbo Experts: Please chime in!
About a month ago I picked up a Frankenstein of a project, any opinions/suggestions are welcomed (good/bad). Previous owner daily drove for 4 years/40K miles on this setup and claims running lean is safer even though less efficient/less power with the Speed Density tune. My goal for this car is to keep it a canyon carver (1-2 HPDE a year) but I'm confused if I should keep it as is or get it re-tuned for more power (how much/safe?). My Corvette specialty shop already did a leak-down test/compression test, inspected the motor/turbo/tranny/diff are in tip-top shape.
1999 C5 FRC setup for daily driving/reliability, made 560whp on 12lbs and 460whp on 6lbs on 91 octane. Runs rich, AFR 14 in idle and 10 or less at WOT based on gauge:
1999 C5 FRC setup for daily driving/reliability, made 560whp on 12lbs and 460whp on 6lbs on 91 octane. Runs rich, AFR 14 in idle and 10 or less at WOT based on gauge:
LS6 swapped (forged/balanced)
Turbocharged (Turbonetics single T76)
Front mount intercooler
Tial waste gate and BOV
Meth injection( not hooked up)
Boost controller(in center console)
Dynojet wideband commander
S.D. tuned
60lb fuel injectors
Walbro 450 fuel pump
Compstar rods
Mahle pistons
ARP bolts
Comp 918 valve springs
Comp Gardened push rods
317 heads
Z06 cam
Last edited by s2kpunisher; 11-23-2018 at 02:45 PM.
11-23-2018, 03:02 PM
#2
Le Mans Master
sounds like it's running rich, which is the safer option (to a point).
with those heads lowering compression (assuming 71cc chambers), you're good for more boost, and with a forged motor, there shouldn't be any worries turning it up - folks safely make more than that all the time on stock long blocks.
with those heads lowering compression (assuming 71cc chambers), you're good for more boost, and with a forged motor, there shouldn't be any worries turning it up - folks safely make more than that all the time on stock long blocks.
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CorvetteBrent (12-08-2018)
11-23-2018, 03:16 PM
#3
Pro
Thread Starter
sounds like it's running rich, which is the safer option (to a point).
with those heads lowering compression (assuming 71cc chambers), you're good for more boost, and with a forged motor, there shouldn't be any worries turning it up - folks safely make more than that all the time on stock long blocks.
with those heads lowering compression (assuming 71cc chambers), you're good for more boost, and with a forged motor, there shouldn't be any worries turning it up - folks safely make more than that all the time on stock long blocks.
11-23-2018, 05:10 PM
#4
Le Mans Master
there're likely a number of reputable LS tuners in SoCal if you're wanting somebody local. others on here can also datalog & email you tune files (requires specific equipment, but any one of them can talk you through that).
speed density tuning ain't a company; it's a way of tuning that runs based off of manifold pressure rather than also using the mass air flow sensor.
speed density tuning ain't a company; it's a way of tuning that runs based off of manifold pressure rather than also using the mass air flow sensor.
11-23-2018, 06:52 PM
#5
Pro
Thread Starter
there're likely a number of reputable LS tuners in SoCal if you're wanting somebody local. others on here can also datalog & email you tune files (requires specific equipment, but any one of them can talk you through that).
speed density tuning ain't a company; it's a way of tuning that runs based off of manifold pressure rather than also using the mass air flow sensor.
speed density tuning ain't a company; it's a way of tuning that runs based off of manifold pressure rather than also using the mass air flow sensor.
Appreciate the input.
Anyone here know of an experienced tuner in SoCal?
11-23-2018, 07:02 PM
#6
Drifting
If you're going to retune and want some more power... highly recommend you get the meth kit up and running or look into converting to E85. 91 octane is already the big limiting factor in your setup. E85 route will probably require all new fuel system though, so maybe the methanol route is more appealing in your case.
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CorvetteBrent (12-08-2018)
11-23-2018, 07:03 PM
#7
Le Mans Master
At 10> AFR you're washing your cylinders down with raw fuel. Absolutely CRAP for power and terrible for your engine. You have probably 60-70 rw available in just the AFR in the tune. I ran turbo's AND nitrous on 11.8-12.0 AFR (on pump gas) with the right plugs and tune. And why speed density? That to me sounds like the tuner didn't know how to tune a mass air system and went with speed density for comfort because he didn't want to hurt a turbo corvette. Do NOT let than human touch your car again. Find a real tuner.
(EDIT: Meth is a waste of money)
(EDIT: Meth is a waste of money)
Last edited by Pb82 Ronin; 11-23-2018 at 07:04 PM.
11-27-2018, 12:35 PM
#8
Instructor
And why speed density? That to me sounds like the tuner didn't know how to tune a mass air system and went with speed density for comfort because he didn't want to hurt a turbo corvette. Do NOT let than human touch your car again. Find a real tuner.
(EDIT: Meth is a waste of money)
(EDIT: Meth is a waste of money)
11-27-2018, 02:47 PM
#9
Le Mans Master
At that power level he's maxxing out the MAF. So you're either adding fuel by cranking the PE table up or skewing other things incorrectly. I'm not defending the tuner, but saying they went to speed density out of comfort is a pretty big leap... especially since most people would consider mass air to be easier to tune "quick and dirty".
11-28-2018, 01:58 PM
#10
Melting Slicks
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CorvetteBrent (12-08-2018)
11-28-2018, 02:09 PM
#11
Burning Brakes
Everyone around here prefers speed density and it’s considered an upgrade. My cars been converted to speed density for years and has great street manners as well as runs well at 18lbs.
For peace of mind, I would have a reputable tuner check out your tune . Being too fat can cause problems.
For peace of mind, I would have a reputable tuner check out your tune . Being too fat can cause problems.
Last edited by junk c5; 11-28-2018 at 02:17 PM.
11-28-2018, 06:38 PM
#12
Pro
Thread Starter
Here’s my number from my mechanic inspection:
Comp test:
140-8
150-7
150-6
150-5
148-4
145-3
147-2
140-1
Leakdown test:
10%-8
10%-7
9%-6
10%-5
11%-4
11%-3
10%-2
10%-1
Guys with Speed Density what are your AFR in WOT?
Comp test:
140-8
150-7
150-6
150-5
148-4
145-3
147-2
140-1
Leakdown test:
10%-8
10%-7
9%-6
10%-5
11%-4
11%-3
10%-2
10%-1
Guys with Speed Density what are your AFR in WOT?
11-29-2018, 06:00 AM
#13
Le Mans Master
that turbo m ight choke a v8 and spike up exh back pressure and it won't be in the efficiency range of the turbo
need to get more specs on that turbo but I'm not a fan of teeny weeny turbos on a v8
don't choke it
Last edited by Rkreigh; 11-29-2018 at 06:02 AM.
11-29-2018, 09:16 AM
#14
Le Mans Master
Everyone around here prefers speed density and it’s considered an upgrade. My cars been converted to speed density for years and has great street manners as well as runs well at 18lbs.
For peace of mind, I would have a reputable tuner check out your tune . Being too fat can cause problems.
For peace of mind, I would have a reputable tuner check out your tune . Being too fat can cause problems.
11-29-2018, 09:19 AM
#15
Pro
Thread Starter
for turbo applications I like around 11.5 afr I'd really recommend a bit more turbo and e85
that turbo m ight choke a v8 and spike up exh back pressure and it won't be in the efficiency range of the turbo
need to get more specs on that turbo but I'm not a fan of teeny weeny turbos on a v8
don't choke it
that turbo m ight choke a v8 and spike up exh back pressure and it won't be in the efficiency range of the turbo
need to get more specs on that turbo but I'm not a fan of teeny weeny turbos on a v8
don't choke it
I want to keep this turbo as is and if necessary just tune for 11.5AFR regardless of power. Is 6psi/12psi too much for this kit?
Forgot to mention it’s tune to boost 6psi from gears 1-2 and 3-6 are 12psi.
Last edited by s2kpunisher; 11-29-2018 at 09:20 AM.
11-29-2018, 09:44 AM
#16
Melting Slicks
11-29-2018, 09:46 AM
#17
Melting Slicks
Previous owner lost receipts so no clue what turbo specs are. Do I have to pull the unit to see a spec on it somewhere?
I want to keep this turbo as is and if necessary just tune for 11.5AFR regardless of power. Is 6psi/12psi too much for this kit?
Forgot to mention it’s tune to boost 6psi from gears 1-2 and 3-6 are 12psi.
11-29-2018, 09:59 AM
#18
Pro
Thread Starter
for turbo applications I like around 11.5 afr I'd really recommend a bit more turbo and e85
that turbo m ight choke a v8 and spike up exh back pressure and it won't be in the efficiency range of the turbo
need to get more specs on that turbo but I'm not a fan of teeny weeny turbos on a v8
don't choke it
that turbo m ight choke a v8 and spike up exh back pressure and it won't be in the efficiency range of the turbo
need to get more specs on that turbo but I'm not a fan of teeny weeny turbos on a v8
don't choke it
11-29-2018, 10:09 AM
#19
Burning Brakes
Last edited by junk c5; 11-29-2018 at 10:10 AM.
11-29-2018, 10:16 AM
#20
Burning Brakes
At bare minimum, the exhaust housing should have numbers indicating its size.
Last edited by junk c5; 11-29-2018 at 10:18 AM.