Made less hp H/C then cam only - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

FathoeSS · 01-14-2021, 06:45 PM

I’m fairly new to the forums but I’m stuck. I have a 2014 m6 with gpi 4ss cam and a pair of their cnc ported heads, e85, 1 3/4 long tubes and 3.91s. Monday I went and got the car tuned with same tuner same dyno. To make the story short I ended making less, not much but still less. My old setup was a btr stage 4 cam I don’t remember the cam specs but with the same setup without heads the car made 497hp 471tq but now with the heads the car put down 487hp and 466tq. After 3 pulls with different timing the car wouldn’t make any less or anymore. My tuner also believes something is holding back the car. The tuner said the car could be degreed incorrectly but if that was true wouldn’t I run into ptv clearance issues? Also I called gpi and they told me that the long tubes are restricting the car and that I should buy 2in long tubes. Just curious if anyone has any thought on what could be going on.

1JEWLDSSRS · 01-14-2021, 06:53 PM

From what I have been reading about LT's on here the past few weeks the 1 3/4 LT's are a hold back on most H/C builds. You really need to switch to at least 1 7/8 to get the most out of the exhaust flow. Most don't want to do the 2's because of clearance issues with steering and frame rails. And yes if the cam was degreed incorrectly you would have some bent valves, from what I have read. Good luck sir.

Bo White · 01-14-2021, 07:08 PM

How long ago was the previous dyno session? Were the dyno numbers both on the same correction factor?

1JEWLDSSRS · 01-14-2021, 07:15 PM

Didn't think of that Bo, there would be a difference as my tuner showed me on mine last year when I had her re-tuned.

FathoeSS · 01-14-2021, 07:17 PM

Bo, The previous dyno session was about 9 months ago and yes both dyno sessions where ran on std smoothing 5 but I also put the car on another dyno reading sae smoothing 5 and the car made the same not number

Bigdumogre · 01-14-2021, 07:39 PM

That’s weird
Actually in for answers

07-SRT · 01-14-2021, 07:58 PM

STD correction will produced higher numbers than SAE corrected. I agree that the headers are probably holding you back some, GPI SS4 is a top end cam that pulls to 7,200+ RPMs. What RPM did they pull to on the Dyno sheet?

FathoeSS · 01-14-2021, 08:50 PM

Srt the car was cranked out to 7k

InFiD3ViL · 01-14-2021, 10:32 PM

How does the car FEEL compared to the BTR setup? You don't mention how it runs in comparison.

I too agree on the headers being a possible restriction. At that power level the car really needs to be able to get rid of that air as efficiently as possible, and those 1 3/4" are likely holding you back a bit - but by how much?

Another possibility since you were running the same dyno, same settings, but a different day is the DA. What was the temp and humidity between the different dyno sessions? That can make a big difference, but seeing as we are smack dab in the middle of winter and even Florida has been nice and cold lately, I doubt that is the real contributor.

Also, were both dyno sessions run on the e85? What percentage was the fuel tested at?

Ashen L99 · 01-15-2021, 02:24 AM

I agree with everyone above. How does the car run? A dyno number is just a measurement tool for tuners. If it’s within 10 numbers I wouldn’t worry about it as long as she runs good. Your headers are a restriction past 7,000 rpm. Car needs to breathe.

I’m not picking on the OP, but why do so many people get so caught up with their dyno number? I can understand if a car was making close to 500 wheel drops to 450 and both cams are max effort but switch cams and lose 1 number and all hell breaks loose. Again, I’m not picking on the OP.

FathoeSS · 01-15-2021, 02:36 AM

Infid3vil, the car feels great it’s hard to compare now with the 3.91s as for fuel content the car is reading about the same if I recall correctly cam only the e content was 77% and this tile around it was 78%

joshnmn · 01-15-2021, 03:12 AM

Was the first number on e or gas? Maybe you’re out of injector on e?

FathoeSS · 01-15-2021, 03:41 AM

Josh, the first number was on e and I don’t think it could be that I’m running out of injector the dc was around 78.

joshnmn · 01-15-2021, 06:36 AM

Gotcha

It was a shot in the dark, bc I’m with you- that doesn’t make any sense.

01-14-2021, 06:45 PM	#1
FathoeSS Drives: Chevrolet Camaro SS Join Date: Jan 2021 Location: Miami Posts: 9 View My Garage	Made less hp H/C then cam only I’m fairly new to the forums but I’m stuck. I have a 2014 m6 with gpi 4ss cam and a pair of their cnc ported heads, e85, 1 3/4 long tubes and 3.91s. Monday I went and got the car tuned with same tuner same dyno. To make the story short I ended making less, not much but still less. My old setup was a btr stage 4 cam I don’t remember the cam specs but with the same setup without heads the car made 497hp 471tq but now with the heads the car put down 487hp and 466tq. After 3 pulls with different timing the car wouldn’t make any less or anymore. My tuner also believes something is holding back the car. The tuner said the car could be degreed incorrectly but if that was true wouldn’t I run into ptv clearance issues? Also I called gpi and they told me that the long tubes are restricting the car and that I should buy 2in long tubes. Just curious if anyone has any thought on what could be going on.

01-14-2021, 06:53 PM	#2
1JEWLDSSRS Drives: 2011 SS-RS Join Date: May 2011 Location: FLORIDA Posts: 11,485	From what I have been reading about LT's on here the past few weeks the 1 3/4 LT's are a hold back on most H/C builds. You really need to switch to at least 1 7/8 to get the most out of the exhaust flow. Most don't want to do the 2's because of clearance issues with steering and frame rails. And yes if the cam was degreed incorrectly you would have some bent valves, from what I have read. Good luck sir. __________________ TSP STAGE 3 CAM,231/246 @112 LSA 614/641 LIFT, CIRCLE D 5C-4200-4500 CONVERTER,LOD INTAKE.CORSA EXHAUST. DSS 1 PC DS. PEGASUS SOLID CRADLE MOUNTS. 486RWHP/475RWTQ.LOTS MORE.

01-14-2021, 07:15 PM	#4
1JEWLDSSRS Drives: 2011 SS-RS Join Date: May 2011 Location: FLORIDA Posts: 11,485	Didn't think of that Bo, there would be a difference as my tuner showed me on mine last year when I had her re-tuned. __________________ TSP STAGE 3 CAM,231/246 @112 LSA 614/641 LIFT, CIRCLE D 5C-4200-4500 CONVERTER,LOD INTAKE.CORSA EXHAUST. DSS 1 PC DS. PEGASUS SOLID CRADLE MOUNTS. 486RWHP/475RWTQ.LOTS MORE.

01-14-2021, 07:39 PM	#6
Bigdumogre Drives: 2012 Camaro SS Join Date: Dec 2019 Location: New York Posts: 1,434	That’s weird Actually in for answers __________________ 2012 Camaro 2SS/RS - CSP Custom Cam 232/240 .615/.615 113 +3, Texas speed CNC heads, FTI billet triple disc converter, K&N cai, Katech ported TB, GPI Ported/rod modded manifold, Texas speed 1 7/8 headers, HFC, Flowmaster 2 chambers with x pipe, Mishimoto CC, MSD wires, Roto fab washer relocation, tru cool 40k trans cooler, apex scoop, Pedders extreme coil overs and much more!!

01-14-2021, 07:58 PM	#7
07-SRT Drives: 2015 Camaro SS Join Date: Sep 2011 Location: Jacksonville, Fl Posts: 713	STD correction will produced higher numbers than SAE corrected. I agree that the headers are probably holding you back some, GPI SS4 is a top end cam that pulls to 7,200+ RPMs. What RPM did they pull to on the Dyno sheet? __________________ 2015 Camaro 2SS Cam/Heads/FBO 498/447 SAE

01-14-2021, 07:08 PM	#3
Bo White Drives: 2015 Summit White 2SS 1LE Join Date: Feb 2012 Location: Vance Alabama Posts: 8,020	How long ago was the previous dyno session? Were the dyno numbers both on the same correction factor?

01-14-2021, 07:17 PM	#5
FathoeSS Drives: Chevrolet Camaro SS Join Date: Jan 2021 Location: Miami Posts: 9 View My Garage	Bo, The previous dyno session was about 9 months ago and yes both dyno sessions where ran on std smoothing 5 but I also put the car on another dyno reading sae smoothing 5 and the car made the same not number

01-14-2021, 08:50 PM	#8
FathoeSS Drives: Chevrolet Camaro SS Join Date: Jan 2021 Location: Miami Posts: 9 View My Garage	Srt the car was cranked out to 7k

01-14-2021, 10:32 PM	#9
InFiD3ViL Drives: 2010 CGM 2SS/RS LS3 Swapped A6 Join Date: Sep 2016 Location: Spring Hill, FL Posts: 4,584	How does the car FEEL compared to the BTR setup? You don't mention how it runs in comparison. I too agree on the headers being a possible restriction. At that power level the car really needs to be able to get rid of that air as efficiently as possible, and those 1 3/4" are likely holding you back a bit - but by how much? Another possibility since you were running the same dyno, same settings, but a different day is the DA. What was the temp and humidity between the different dyno sessions? That can make a big difference, but seeing as we are smack dab in the middle of winter and even Florida has been nice and cold lately, I doubt that is the real contributor. Also, were both dyno sessions run on the e85? What percentage was the fuel tested at? __________________ 2010 CGM Camaro 2SS LS3 Swapped A6 - GPI LS3 SS1 .647/.638, (224/237, 112 +4, 7º overlap) on CamMotion 8620 core, BTR Platinum .660" Dual Spring kit w/titanium retainers, CHE bronze trunnion upgrade, stock heads milled @ .015, Melling HV 10296 oil pump, TSP 1-7/8" long tube headers (W/Catless Off-road Pipes), Corsa Xtreme 3" Catback, GPI Ported/Rod Mod Intake, Stage 2 Ported Throttle Body, Vararam OTR CAI, Mike Norris Gen 2 catch can + GM 1LE clean side separator, 160º thermostat - Megan Racing adjustable coilovers (lowered 1.75"), MRR M017 10/11" wheels-Tuned by Ryan @ GPI

01-15-2021, 02:24 AM	#10
Ashen L99 Drives: Ashen grey, 1SS, L99 Join Date: Aug 2016 Location: Oklahoma Posts: 527	I agree with everyone above. How does the car run? A dyno number is just a measurement tool for tuners. If it’s within 10 numbers I wouldn’t worry about it as long as she runs good. Your headers are a restriction past 7,000 rpm. Car needs to breathe. I’m not picking on the OP, but why do so many people get so caught up with their dyno number? I can understand if a car was making close to 500 wheel drops to 450 and both cams are max effort but switch cams and lose 1 number and all hell breaks loose. Again, I’m not picking on the OP. __________________ Roto-fab CAI, Nick Williams 102mm TB, LOD X1 V3 intake manifold, GMPP LS3 heads, Night Fury cam, TSP 2” long tubes, Corsa ZL-1 catback, Nitrous Outlet 102mm plate kit/150 shot, NGK BR7EF plugs with Taylor plug wires, DSX flex fuel kit, ZL-1 fuel pump and injectors, B&M deep trans pan, Yank 3400 converter, 3.45s with BMR Delrin bushings, mishimoto 169° Thermostat, GM ground effects, T-Rex upper grill, Z/28 Spoiler, Lolly pop Lime brake calipers, ZL1 10 spoke wheels, 12” subwoofer, and custom paint matched interior.

01-15-2021, 02:36 AM	#11
FathoeSS Drives: Chevrolet Camaro SS Join Date: Jan 2021 Location: Miami Posts: 9 View My Garage	Infid3vil, the car feels great it’s hard to compare now with the 3.91s as for fuel content the car is reading about the same if I recall correctly cam only the e content was 77% and this tile around it was 78%

01-15-2021, 03:12 AM	#12
joshnmn 2&THEHIT Drives: 5th Gen Camaro; 5th Gen Ram 3500 Join Date: Mar 2018 Location: Garner, NC Posts: 1,013 View My Garage	Was the first number on e or gas? Maybe you’re out of injector on e?

01-15-2021, 03:41 AM	#13
FathoeSS Drives: Chevrolet Camaro SS Join Date: Jan 2021 Location: Miami Posts: 9 View My Garage	Josh, the first number was on e and I don’t think it could be that I’m running out of injector the dc was around 78.

01-15-2021, 06:36 AM	#14
joshnmn 2&THEHIT Drives: 5th Gen Camaro; 5th Gen Ram 3500 Join Date: Mar 2018 Location: Garner, NC Posts: 1,013 View My Garage	Gotcha It was a shot in the dark, bc I’m with you- that doesn’t make any sense.