GT350 vs. Z/28

[Fenderaddict2]

Yeah just watched the race. Sad to see the the Camaros up front.

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[thePill]

Yeah just watched the race. Sad to see the the Camaros up front.

Pratt Miller Camaro's dominate GT and Riley ZL1's were competitive in SCCA GTS. That's just the way it is...another reason I always push for Factory Racing. Initially, cars like the Camaro were the reason the Boss and M3 got restrictions. How much of an aftermarket advantage do they need?

They just wanted to use the "Z/28" badge in IMSA and the ZL1 in SCCA. Neither of those two cars were developed for racing. They need major changes to be permitted to race. Might as well go back to the FR500/GT.R Mustangs then...because that is pretty much what they are using. Only it's built completely by a 3rd party.

 

[Stuntman]

Isn't multimatic a 3rd party who builds the 302Rs?

I think the GS class has been well over 400hp for many years.

 

[thePill]

Isn't multimatic a 3rd party who builds the 302Rs?

I think the GS class has been well over 400hp for many years.

The Boss 302R is delivered by Ford Racing, Multimatic Co-developed the car in during the 2010 season (Boss GT). The car is a "Turn Key" and is ready to run. The Z/28.R is actually a regular Camaro. No, it is NOT taken from the 500 OEM cars. It is just a V8 Camaro. That 5th Gen is shipped from Chevy to Pratt Miller (or Riley in some cases) and turned into a Z.28.R from there.

Pratt does not decontent a 2014 z28, they make their own from a base or SS. The LS7 crate engine is sealed and shipped from Chevy. Everything else is aftermarket.

The entire class is near OEM, except for the Pratt and Riley cars.

As I mentioned before, Chevy did not have a competitive option for the Boss. They NEED 7 liters and a Carbon Fiber body. They are dead in the water with the 6.2 LS3, they still need help and probably money. The couldn't get it done with a 6.2, the 1LE failed really bad in T2 and they require 3rd Party engineers to make it so. The GT.R in Tudor, built by Pratt, the GTS ZL1 (still lol'ing), built by Riley, The GS.R, built by Riley and now Z28.R is built by Pratt (better cars). Oh well, as long as it looks like a z28... For a car heavily marketed at road racing, they actual product should be on the track.

 

[thePill]

The maximum output for Continental Tire is 400hp. The Boss and M3 have a 57mm plate and the M3 has two (36x2) plates. The Z/28.R has an 80mm plate... Initially, I thought that measurement was the restriction based on previous conversations. It means the stock throttle body has been choked down from a 90mm to a 57mm. It is required to get the Boss and M3 below 400hp...

Taking the LS7 from 90mm to 80mm is kinda cheating... That won't decrease power levels by over 100hp. It's likely that the Z28 is closer to 500...

I'm still not sure why they are allowed to do this but, it's NASCAR now... Fair and equal I guess...

 

[Norm Peterson]

I'm still not sure why they are allowed to do this but, it's NASCAR now... Fair and equal I guess...

Naw . . . just a fantasy league either virtually on Yahoo or in the metal. Entertainment value.


Norm

 

[FATTBoss]

I have a friend who owns Boss 302R #13 and he was here testing the car yesterday. I took a look at the rear wing and noticed the paint was cracking at the base of the pedestals. I asked in someone leaned on the spoiler and was told no, they just produce that much downforce.

I noticed a few posts back someone claimed the Boss didn't use OEM size front rotors, they are delivered, even the original R, with 14" fronts, same as my street Boss came with stock. The difference being that they are lighter two piece rotors and a slightly different Brembo calipers. Since my buddy switched to the 15" setup currently allowed in the rules, as soon as they feel comfortable with the package, the 14" race setup will be going on my street Boss.

The one thing they told me about the new setup is that it gives extra swept area toward the center of the disc, as there isn't much room to grow outwards since they are limited to a 18" wheel.

I wasn't surprised that Stevenson got a win in the new Camaro, but I would feel pretty hollow about it if I were them running a 2.0 liter advantage in size over their nearest competitor, and 3.0 liters over most everyone else. What's the BMW size? 4.4? If IMSA continues to allow this car and doesn't relax the restrictions on the other teams, I may have to stop watching.

 

[Sabre]

The #158 Miller/Multimatic Mustang driven by Billy Johnson and Ian James would have shown better, but suffered clutch problems during the first segment when Billy was driving.

The restrictor on the Mustang, is a ring, that sits inside the air intake tube...up against the front face of the throttle body and not a plate that goes between the throttle body and the intake.

 

[Stuntman]

I think the GSR almost won the championship last year, so you can't really say its uncompetitive.

The 302R is also just a mustang chassis that was taken off the production line and not from the set amount of BOSS street cars so I don't see how that's any different from the camaro.

Fwiw the M3s 414hp 4L motor can easily make 470hp from a tune and removing the cat on pump gas. The S65 is very responsive to octane so a race ecu with a race exhaust and 100 octane fuel would make a bit more than that. The question becomes how much HP will the engine lose from the mandated restrictor. Same for the Boss' 444hp 5.0 which will make more power with a carless exhaust on 100 octane but with a restrictor. Then the 500hp LS7 will also make more power pre-restrictor with no cats and optimizing the tune for 100 octane.

 

[FATTBoss]

I think the GSR almost won the championship last year, so you can't really say its uncompetitive.

The 302R is also just a mustang chassis that was taken off the production line and not from the set amount of BOSS street cars so I don't see how that's any different from the camaro.

Fwiw the M3s 414hp 4L motor can easily make 470hp from a tune and removing the cat on pump gas. The S65 is very responsive to octane so a race ecu with a race exhaust and 100 octane fuel would make a bit more than that. The question becomes how much HP will the engine lose from the mandated restrictor. Same for the Boss' 444hp 5.0 which will make more power with a carless exhaust on 100 octane but with a restrictor. Then the 500hp LS7 will also make more power pre-restrictor with no cats and optimizing the tune for 100 octane.

What you are missing by posting what a modded car can produce is that these are not modified. They also run on pump 93, not 100. The ECU is mandated to be a factory unit, and any outside attempt to tune it is against the rules. GM teams got in trouble in one series last year for hacking into the ECU using OnStar, and then reloading the factory settings after the race. Aside from balancing, each motor is sealed aftyer assembly by the respective apporoved builder. Roush gets the Boss engines, a company in CA the Porsches and so on.

Any benefit of the cat is negated by the restrictor installed.

 

[FATTBoss]

As per IMSA car regulations page 5:

Grand Sport​

​

[FONT=Arial,Arial][FONT=Arial,Arial](GS) [/FONT][/FONT]and Street Tuner [FONT=Arial,Arial][FONT=Arial,Arial](ST) [/FONT][/FONT]Specific Car Regulations 20143 ​

[FONT=Calibri,Calibri][FONT=Calibri,Calibri]5
[/FONT][/FONT][FONT=Arial,Arial Narrow][FONT=Arial,Arial Narrow]Ford Mustang Boss 302R GT GS
[/FONT][/FONT][FONT=Arial,Arial Narrow][FONT=Arial,Arial Narrow]As submitted by Ford and as approved by IMSA, according to the Homologation document.
Final Drive: 3:73:1
Fuel capacity: 18.5 gal.
Weight: 3315 lbs OR 3360 lbs as per Permitted replacement components #11
Tire size: 275/35/18
Maximum RPM 8000
 Must use 57 mm air inlet restrictor as supplied.
 Must use OEM ECU as supplied by Ford Racing.
 Must use unmodified exhaust manifold as supplied with engine. Permitted band clamp attachment.
 Maximum rear camber allowance is a total of .3 degrees (Left and right combined). The maximum delta between left and right side camber is .1 degrees.
Engine must be sealed as provided by Roush Yates Racing Engines
[/FONT][/FONT][FONT=Arial,Arial Narrow][FONT=Arial,Arial Narrow] Engines may be built by any engine builder. Engine must be submitted to Roush Yates for physical inspection and power audit.
 Engine physical inspection will include a visual inspection of the crank, rods and pistons.
 Physical inspection will include an evaluation of cylinder head ports (intake and exhaust.)
 Physical inspection will include an evaluation of camshaft events.
 Physical inspection will include an evaluation of intake manifold and throttle bodies.
 Power audit includes running engine on dynamometer to establish compliance to IMSA accepted power levels.
 Audit will include spark and fuel slew to confirm max power level.
 If engine is found compliant in both physical inspection and power audit documentation of engine number and seal number will be recorded on-site, provided to IMSA and engine will be sealed and returned to customer.
[/FONT][/FONT][FONT=Arial,Arial Narrow][FONT=Arial,Arial Narrow]Approved Modifications
[/FONT][/FONT][FONT=Arial,Arial Narrow][FONT=Arial,Arial Narrow]1. Fuel Cell required mounting behind rear axle. Mounting to be with short axis of fuel cell can along length of car and long axis along height of car.
2. Battery relocation to right rear of trunk.
[/FONT][/FONT][FONT=Arial,Arial Narrow][FONT=Arial,Arial Narrow]Permitted replacement components
[/FONT][/FONT][FONT=Arial,Arial Narrow][FONT=Arial,Arial Narrow]1. One piece drive shaft, part number M-4602-S, fordmotorsport.com
2. Multimatic Motorsports, Inc. mono-ball in front upper third link mount.
3. Front rotor 355 mm.
4. Front caliper upgrade per regulations.
5. Multimatic Motorsports, Inc. ABS part number 7FRT-2C353-AA
6. Multimatic Motorsports, Inc. Rear wing 605-SW100 with pedestal modification and mounting shims. (Mounting to be at same angle of attack as 2005 Mustang) Permitted Boss front grill as produced for road car.
7. Alternate connecting rod. (Manley Part # 14318)
8. 2013 Boss 302 front fascia part# DR33-16C928-AAW, hood part# DR3Z-16612-A.
9. Boss R front grill part number M-8200-MBRA and rear taillight panel part# DR33-13B504-AC, DR33-13B505-AC and associated components and hardware.
10. 2013 Boss 302 lower front "spoiler" or "splitter" DR3Z-17626-BA
11. 2013 GT500 brake package, (Front calipers P/N XB10511LH, P/N XB 10512RH; disc 09852874LH, 09852884RH; rear rotor DR3Z-2C026). Teams that opt to use this package are not permitted dimensional tolerances or front caliper upgrade. If used in combination with Bosch ABS controller, or Ford Racing ABS Module M-2353-CA or Module, Hydraulics and Bracket Assembly M- 2353-BA controller, Minimum weight shall be 3360.

Link: http://www.imsa.com/sites/default/files/uploads/Comp.%20Bulletin%20%2314-58.pdf

Page 4:

4​

[FONT=Arial,Arial Narrow][FONT=Arial,Arial Narrow]Chevrolet Camaro Z/28.R GS
[/FONT][/FONT][FONT=Arial,Arial Narrow][FONT=Arial,Arial Narrow]Provided by Chevrolet, built by Pratt Miller and as approved by IMSA.
Final Drive: 3.73
Fuel capacity: 20.5 gal.
Refueling Restrictor: 1.0 inch
Weight: 3400
Engine Restrictor: 75.0 mm (-5mm)
Maximum RPM: 6300 (-600RPM)
Engine shall be sealed by GM Powertrain.
Vehicle is conditionally approved
Vehicle is granted a waiver on Article 2-1.1 of the Technical Regulations

Hmmm, gets in with a waiver...

Probably very similar to the GS.R in prep which gets all the lightweight go fast and suspension goodies listed:

Chevrolet Camaro GS
[FONT=Arial,Arial Narrow][FONT=Arial,Arial Narrow]As provided by Chevrolet, built by Riley Technologies & approved by IMSA.
Final Drive: 3.45
Fuel capacity: 20 gal.
Weight: 3300 lbs.
Tire size 275/35/18.
Maximum RPM 6600
 Must use Bosch MS 4.3 ECU
 Stock, unmodified, LS-3 engine. No internal engine modifications are permitted unless listed.
 Must use complete unmodified OEM air intake system.
Engine must be sealed as provided by CRD Motorsports
[/FONT][/FONT][FONT=Arial,Arial Narrow][FONT=Arial,Arial Narrow] Engines may be built by any engine builder.
 Engine must be submitted to CRD for physical inspection and power audit.
 Engine physical inspection will include a visual inspection of the crank, rods and pistons.
 Physical inspection will include an evaluation of cylinder head ports (intake and exhaust.)
 Physical inspection will include an evaluation of camshaft events.
 Physical inspection will include an evaluation of intake manifold and throttle bodies.
 Power audit includes running engine on dynamometer to establish compliance to IMSA accepted power levels.
 Audit will include spark and fuel slew to confirm max power level.
 If engine is found compliant in both physical inspection and power audit documentation of engine number and seal number will be recorded on-site and provided to IMSA.
 Engine will be sealed and returned to customer.
[/FONT][/FONT][FONT=Arial,Arial Narrow][FONT=Arial,Arial Narrow]Approved Modifications
[/FONT][/FONT][FONT=Arial,Arial Narrow][FONT=Arial,Arial Narrow]1. Caliper upgrade as per rules.
2. Battery relocation to right rear of trunk.
3. Fuel Cell required mounting behind rear axle. Mounting to be with short axis of fuel cell can along length of car & long axis along height of car.
4. Dry Sump (3 stage scavenge)
[/FONT][/FONT][FONT=Arial,Arial Narrow][FONT=Arial,Arial Narrow]Permitted replacement components
[/FONT][/FONT][FONT=Arial,Arial Narrow][FONT=Arial,Arial Narrow]1. Riley Technologies Rear toe link offset bushing, part # Y27-016
2. Riley Technologies Single piece drive shaft, part # Y24-001
3. Replace rod bolts.
4. Riley Technologies Dry sump pan, part # Y21-1005M
5. Riley Technologies Light weight doors, part # Y01LH / Y01RH
6. Riley Technologies Light weight hood, part # Y01- HOOD
7. Riley Technologies Light weight deck lid, part # Y01- DECKLID
8. IMSA approved ABS controller.
9. Riley Technologies Offset ½ inch differential mount bushing
10. Rear brake caliper from V-6 model
11. Riley Technologies front trailing arm bushing. (P/N Y12-015, 016, COM 14-T70)
12. Riley Technologies Throw out slave cylinder. (P/N TBD)
13. Aftermarket RAM single-disc Clutch/Flywheel. (P/N TBD)
14. Inner Lower Control arm spherical bearings part # Y12-100F & Y27-1001R
15. GM Rear Spoiler Kit Part # 92234283
16. Quartermaster Part# Y24-2000 replacement Clutch/flywheel.
17. chin spoiler GM P/N 22745060
18. Pfadt spherical bearing PN A-1208 Rear upright upper arm bearing

As you can clearly see, if you read it, the Mustang Boss 302R is much closer to OEM than any of the Camaros. I find it funny that they don't list all the stuff they were allowed on the Z/28R
[/FONT][/FONT][/FONT][/FONT][/FONT][/FONT]

 

[FATTBoss]

And another thing missing from the Z/28 specs, no mention of a dyno run to verify compliance to the IMSA "power audit"

 

[FATTBoss]

And lastly, the Technical regulation the car was exempted from:

​

2-1.1
Eligible Cars are ordinarily those described in manufacturer’s catalogs, produced at a minimum rate of 500 units per year, and available for purchase through normal dealer outlets in the U.S. 30 days or more prior to competing in an Event. Exemption from minimum production requirements must be approved by IMSA.

Linky:http://www.imsa.com/sites/default/files/uploads/CTSC 2014 Technical Regulations 1-18-14.pdf

 

[Stuntman]

"Vehicle is conditionally approved"(for the z28)

The boss does not have the factory transmission.

 

[FATTBoss]

"Vehicle is conditionally approved"(for the z28)

The boss does not have the factory transmission.

Oh that's right, it has the Tremec, same as the GT500 and Camaro. Wow, all that and that's what you come up with?

I take conditionally approved to mean they can yank it at any time. Fact remains the rest of the teams are allowed only so much and are tested to make sure they comply with the HP limit in the Series, and no mention of that in the Z/28R specs. If the situation were reversed, you would be crying "FOUL!", and rightfully so. The Camaro never should have been approved for the class and I can't believe the other teams aren't bitching up a storm about it. The only ones who shouldn't be complaining are the Porsche teams who continually sandbagged last season, and are still doing so this year.

Their car wieghs 3050lbs and probably makes close to the same power as other teams.

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