Dyno Pull yesterday (OBX Headers) - ZR-1 Net Registry Forums

Shrek · 02-12-2012

After 2 months of thrashing on the track conversion, I finally got the car to my buddies shop for a track alighnment. While there, we strapped it down for a quick dyno pull to make sure all of the changes worked properly (OBX headers/Plenum coolant elim/Secondary vac elim)
Only had time for one quick pull, but I'm pleased with the numbers! 339.8 HP/342.2 TQ. That's compared to 309 HP/310 TQ in 2003 through the stock manifolds with Flowmaster cat back. The Flowmasters sound even better throught the headers!!!

***EDIT***OOPS.....I just went through all of my files on the car, and the first numbers were through the stock exhaust (NOT THE FLOWMASTER CAT BACK)***

Headed to VIR next weekend for her first event!

Done so far!
Vansteel coilover package
Banski spherical/heim camber rods
Banski spherical/heim toe rods
Banski spherical/heim trailing arm rods
SPC spherical/heim front upper A-arms
Exotic Muscle adjustable sway bar end links
Del-A-Lum lower A-arm bushings
Poly sway bar bushings (w/front relocation block)
DRM camber rod brackets
DRM trailing arm brackets
Carbotech pads
DRM brake bias spring
Nitto NT-01
Hurst short throw shifter
C beam plates
Elite Engineering oil catch can
Block plenum/TB coolant flow
Removed secondary vac, actuators & blades
OBX headers
Removed secodary vac system
Haibeck reprogram for secondaries & headers
DRM Chassis bar
Kirkey seats
Crow harnesses
MOMO steering wheel and adapter (2 ohm resistor for airbag light)

ZZZZZR1 · 02-12-2012

Very cool!

Love to see some video of that beast in action!

David

Paul Workman · 02-12-2012

339.8??

Curious... have you done a compression check, and if so, do you remember what it did?

30 is a good bump for headers, but seems there is more to be had at that. Could be the dyno too, I guess. Anybody else? ?

Shrek · 02-12-2012

Wish I could say it was just the headers, but I can't!
2 different Dyno jets.
New injectors last year.

***I just went through all of my files on the car, and the first numbers were through the stock exhaust (NOT THE FLOWMASTER CAT BACK)***

sammy · 02-12-2012

i believe the difference was compared to a totally stk exhaust . kinda tough to figure the individual improvement with all the changes that were made ,. as dominic shared in an earlier thread , one needs to chassis dyno tune the car to get the most out of ones changes . generic tunes only go so far . jmho . but 30 more hp will stiil be alot of fun

Marc Haibeck · 02-12-2012

Road racers should be aware that water pump cavitation occurs at 6100 rpm. Engine speed over 6100 rpm for more than a few seconds can overheat the engine. I know of two LT5’s that have pushed back head gaskets at VIR.

The common scenario is the driver is busy driving and the check engine light goes on because the coolant has reached the 250 degrees F. high temperature limit. The driver becomes aware of the situation when the engine control system disables the secondary port throttles.

If the driver up shifts and runs the engine at less than 5500 rpm, the engine temperature will drop rapidly as the coolant circulation resumes. The engine temperature will usually return to a normal 210 degrees or so in about half of a lap.

The failure mechanism is that the aluminum liners expand much more than the steel head bolts. The gasket gets crushed and then fits loose after the engine cools. Normal driving eventually pushes the loose fitting gasket off the liner at the exhaust coolant passage.

Reducing the pump speed can raise the cavitation speed. A ZR-1 Products under drive water pump pulley will raise the cavitation speed to 6400 rpm. If an under drive water pump pulley is used with an ATI under drive crankshaft pulley the cavitation speed will increase to 7500 rpm. Use of the two pulleys may cause the engine to run hotter at idle with the AC on.

LGAFF · 02-12-2012

Marc is there a way to ring the head....and would that help this issue??

mike100 · 02-12-2012

Seems a little odd that the rwTQ is higher than rwhp. Mine put out around 330 rwTQ and about 350hp. That was run in 3rd gear (stock manifolds). I have heard discussions that some cars will show 5-10 hp more if you run in 4th. Then there is the individual dyno and the elevation of the test etc etc.

The one thing that does jive is that headers/exhaust are good for an easy 30 rwhp.

GOLDCYLON · 02-12-2012

Nice numbers

Marc Haibeck · 02-12-2012

Hi Lee,

The OE gaskets work well up to 650 hp if the engine does not detonate excessively or overheat. A wire ring can help lock the OE gasket in place. However the modern solution is to use a MLS head gasket. It’s easier to install MLS gaskets than to modify the cylinder heads.

The OE gasket crushes to fit. It does not rebound much when the clamping force is increased and then reduced. A MLS gasket will spring back if it is over-clamped on a hot engine. We use MLS head gaskets on all of our assemblies.

Still the fundamental problem of overheating should be addressed directly. Head gaskets are easy to replace compared to other damage that an overheating engine might sustain.

02-12-2012	#1
Shrek Join Date: Sep 2010 Location: Currituck, NC Posts: 246	Dyno Pull yesterday (OBX Headers) After 2 months of thrashing on the track conversion, I finally got the car to my buddies shop for a track alighnment. While there, we strapped it down for a quick dyno pull to make sure all of the changes worked properly (OBX headers/Plenum coolant elim/Secondary vac elim) Only had time for one quick pull, but I'm pleased with the numbers! 339.8 HP/342.2 TQ. That's compared to 309 HP/310 TQ in 2003 through the stock manifolds with Flowmaster cat back. The Flowmasters sound even better throught the headers!!! *EDITOOPS.....I just went through all of my files on the car, and the first numbers were through the stock exhaust (NOT THE FLOWMASTER CAT BACK) Headed to VIR next weekend for her first event! Done so far!** Vansteel coilover package Banski spherical/heim camber rods Banski spherical/heim toe rods Banski spherical/heim trailing arm rods SPC spherical/heim front upper A-arms Exotic Muscle adjustable sway bar end links Del-A-Lum lower A-arm bushings Poly sway bar bushings (w/front relocation block) DRM camber rod brackets DRM trailing arm brackets Carbotech pads DRM brake bias spring Nitto NT-01 Hurst short throw shifter C beam plates Elite Engineering oil catch can Block plenum/TB coolant flow Removed secondary vac, actuators & blades OBX headers Removed secodary vac system Haibeck reprogram for secondaries & headers DRM Chassis bar Kirkey seats Crow harnesses MOMO steering wheel and adapter (2 ohm resistor for airbag light) Last edited by Shrek; 02-12-2012 at 12:07 PM.

02-12-2012	#2
ZZZZZR1 Banned BANNED Join Date: Oct 2006 Location: MD Posts: 3,674	Re: Dyno Pull yesterday (OBX Headers) Very cool! Love to see some video of that beast in action! David

02-12-2012	#3
Paul Workman Join Date: Nov 2007 Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri Posts: 6,466	Re: Dyno Pull yesterday (OBX Headers) 339.8?? Curious... have you done a compression check, and if so, do you remember what it did? 30 is a good bump for headers, but seems there is more to be had at that. Could be the dyno too, I guess. Anybody else? ?

02-12-2012	#4
Shrek Join Date: Sep 2010 Location: Currituck, NC Posts: 246	Re: Dyno Pull yesterday (OBX Headers) Wish I could say it was just the headers, but I can't! 2 different Dyno jets. New injectors last year. *I just went through all of my files on the car, and the first numbers were through the stock exhaust (NOT THE FLOWMASTER CAT BACK)*

02-12-2012	#5
sammy Join Date: Jun 2010 Location: Lone Pine, CA Posts: 580	Re: Dyno Pull yesterday (OBX Headers) i believe the difference was compared to a totally stk exhaust . kinda tough to figure the individual improvement with all the changes that were made ,. as dominic shared in an earlier thread , one needs to chassis dyno tune the car to get the most out of ones changes . generic tunes only go so far . jmho . but 30 more hp will stiil be alot of fun

02-12-2012	#6
Marc Haibeck Join Date: May 2007 Location: Addison IL Posts: 250	Re: Dyno Pull yesterday (OBX Headers) Road racers should be aware that water pump cavitation occurs at 6100 rpm. Engine speed over 6100 rpm for more than a few seconds can overheat the engine. I know of two LT5’s that have pushed back head gaskets at VIR. The common scenario is the driver is busy driving and the check engine light goes on because the coolant has reached the 250 degrees F. high temperature limit. The driver becomes aware of the situation when the engine control system disables the secondary port throttles. If the driver up shifts and runs the engine at less than 5500 rpm, the engine temperature will drop rapidly as the coolant circulation resumes. The engine temperature will usually return to a normal 210 degrees or so in about half of a lap. The failure mechanism is that the aluminum liners expand much more than the steel head bolts. The gasket gets crushed and then fits loose after the engine cools. Normal driving eventually pushes the loose fitting gasket off the liner at the exhaust coolant passage. Reducing the pump speed can raise the cavitation speed. A ZR-1 Products under drive water pump pulley will raise the cavitation speed to 6400 rpm. If an under drive water pump pulley is used with an ATI under drive crankshaft pulley the cavitation speed will increase to 7500 rpm. Use of the two pulleys may cause the engine to run hotter at idle with the AC on.

02-12-2012	#7
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,180	Re: Dyno Pull yesterday (OBX Headers) Marc is there a way to ring the head....and would that help this issue?? __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359

02-12-2012	#8
mike100 Join Date: Feb 2011 Location: San Marcos CA Posts: 1,786	Re: Dyno Pull yesterday (OBX Headers) Seems a little odd that the rwTQ is higher than rwhp. Mine put out around 330 rwTQ and about 350hp. That was run in 3rd gear (stock manifolds). I have heard discussions that some cars will show 5-10 hp more if you run in 4th. Then there is the individual dyno and the elevation of the test etc etc. The one thing that does jive is that headers/exhaust are good for an easy 30 rwhp.

02-12-2012	#9
GOLDCYLON Join Date: May 2007 Location: Peoria, AZ Posts: 9,120	Re: Dyno Pull yesterday (OBX Headers) Nice numbers __________________ GOLDCYLON - 91 ZR-1 #2014 GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's) GOLDCYLON - 11 CTS-V Arizona State Director 91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat 90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat 11 RED/GREY CTS-V