GT350 vs GT350R Engine Differences?

Tob · Jun 27, 2018

ANGREY said:
So does Ford engine dyno with the exhaust or do they wheel dyno?

If they engine dyno, it seems weird they'd do it with the whole exhaust system as well. If they wheel dyno, as I stated earlier, the R is going to have higher hp and torque numbers because the drivetrain is different. Resonators would probably be a very miniscule effect, but wheels that are 17 lbs lighter are going to give higher HP outputs on the rollers and slightly shorter (artificial gearing) are going to result in a bump in torque as well.

Among the many tests Ford does, one of them is to test to the SAE J1349 "Surface Vehicle Standard" that (in essence) measures the power for a given engine. You can pay to obtain the results from SAE. For example, you can find out more about the 2018 Mustang GT SAE test from here...

CPFD1_18MUSGT91: J1349 Certified Power Engine Data for Ford as used in 2018 Mustang GT 91 RON - Level 1 - SAE International

The procedure has room for differing test methods. A “fully equipped” engine is required for the net power and torque test and that includes the exhaust system.

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwju6IbX2vTbAhVwuVkKHfj2AmMQFggpMAA&url=http://www.mie.uth.gr/ekp_yliko/SAE_%CE%94%CE%A5%CE%9D%CE%91%CE%9C%CE%9F%CE%9C%CE%95%CE%A4%CE%A1%CE%97%CE%A3%CE%97_%CE%9C%CE%95%CE%9A.pdf&usg=AOvVaw0cTiFJiy7xKBVUb8K2_3IR

A complete series production Exhaust System (including mufflers, active catalytic converters, resonators) or any laboratory system that provides equivalent restriction at the peak power engine speed. If a complete vehicle exhaust system is not used, the laboratory system must include the vehicle system at least through the first major restriction (e.g., close-coupled catalytic converter.) It is strongly recommended that a full vehicle exhaust be used with four-cylinder engines that are typically most sensitive to exhaust system tuning. Procedures for determining application specific exhaust backpressure are given in section 9.

For transient vehicle testing...

9.1.1 VEHICLE EQUIPMENT

The test must be conducted with a vehicle matching as closely as possible the intended design for series production. Exhaust system and charge air cooler design and engine mass flow must match production intent. Slight deviations are allowable as are typical of pre-production parts.

9.1.3 EXHAUST PRESSURE MEASUREMENT

Instrument the vehicle with pressure probe(s) installed downstream of the exhaust runner collector for each exhaust manifold. The same method and location of exhaust pressure measurement used in the vehicle must be used in the subsequent dynamometer net power test to set exhaust backpressure. For turbocharged engines, backpressure must be measured downstream of the turbine.

9.3
Application of Vehicle Transient Data to Net Power Test The exhaust backpressure, charge air cooler parameters, and engine control parameters shall be determined by averaging the transient vehicle test data for all test runs. The dynamometer net power test shall be controlled at each speed set point to the averaged parameters recorded during the vehicle test. The exhaust backpressure applied to the dynamometer net power test can be set with a valve or orifice plate sized and located to match the average vehicle transient backpressure at the engine's peak power speed.

Here's an example of a J2723 test procedure done.

http://www.gmpowertrain.com/PowertrainFiles/Engine/Plots/Insignia_Buick Regal gas LHU.pdf

Tob · Jun 27, 2018

ANGREY said:
Moreoever, why would you dyno the 350 engines on a full exhaust without resonators, and then separately dyno the power plants that go in the R separately with a different exhaust (sans resonators)? If the two plants are supposedly the same, why the two tests? And if they didn't do it that way, how were they supposed to see a difference between them?

I'm just asking questions to a theory that was thrown out about variances with the resonators being the culprit. The only way for that to be true is if A) Ford did the engine dyno's with full OEM to tip exhaust setups and B) Ford did separate tests for the motors that go in the R's with R style exhaust and motors that go in the regular 350 with 350 style exhaust.

The exhaust systems are not the same hence the testing done. In the end, the difference was small enough to not need to gain individual certifications for each.

And what Pericak alluded to isn't a theory. It has been mentioned elsewhere but here's one example.

One of the weight-saving measures was to remove the exhaust resonators that are fitted to the standard GT350. That means the GT350R will be louder and should produce a teensy bit more horsepower, though Pericak says Ford won’t recertify the 5.2-liter flat-plane V-8 engine so it will get the same horsepower and torque rating as the non-R. But enthusiasts will know their GT350R makes just a little bit more power.

http://www.automobilemag.com/news/6-things-we-learned-about-the-ford-shelby-gt350r-mustang/

ANGREY · Jun 27, 2018

I agree that the R makes a "little bit" more power, but it doesn't have anything to do with the ENGINE, it has to do with the exhaust restriction.

Thanks for the clarifications, it's interesting. So what others alluded to isn't apples/oranges. The engines are identical, it's just what they're mated to that produces differences in measured outputs.

Tob · Jun 27, 2018

ANGREY said:
I agree that the R makes a "little bit" more power, but it doesn't have anything to do with the ENGINE, it has to do with the exhaust restriction.

Thanks for the clarifications, it's interesting. So what others alluded to isn't apples/oranges. The engines are identical, it's just what they're mated to that produces differences in measured outputs.

The exhaust system has an impact on the power produced by the engine. Testing standards require the system (or a methodology that reproduces what the exhaust system would do) to be in place when testing occurs. In that context and in this case, the GT350R produced slightly more power than the regular GT350.

GT Premi · Jun 28, 2018

Which all brings me back to the question of why the use of the stickers to differentiate the engines on the assembly line. Perhaps to let the assemblers know which exhaust system to bolt up to it? But that would be superfluous since all the parts move down the assembly line in order of the vehicle they're being fitted to.

JAJ · Jun 28, 2018

GT Premi said:
Which all brings me back to the question of why the use of the stickers to differentiate the engines on the assembly line. Perhaps to let the assemblers know which exhaust system to bolt up to it? But that would be superfluous since all the parts move down the assembly line in order of the vehicle they're being fitted to.

So, think about it this way: they have to mark the parts for the vehicle type they're going into. They could just put an "SVT" label on the engine (like they do on the suspension parts) or they can lovingly attach a GT350 tag to each of these hand-built wonders. By the time each engine is built, the VIN is on it, so they know which car that particular engine will be going into, so they have no problem putting a GT350R label on some engines and GT350 labels on the rest. It's a nice touch, really, even if it doesn't mean a darned thing.

GT Premi · Jun 29, 2018

JAJ said:
... It's a nice touch, really, even if it doesn't mean a darned thing.

It'll add some value 30 years from now. It'll also cause headaches for restorers trying to find or reproduce those stickers!

Gogoggansgo · Jun 29, 2018

Ford didn’t feel the small changes to the R engine are worth the mention and I’m sorry but the resonators really don’t restrict any air flow. They’re literally little glass packs to lower the DB rating. The wheels is where the Rs have any gain over a run of the mill gt350

Gogoggansgo · Jun 29, 2018

I need to end this lol. I’ve asked this question too some of the engineers at my ford plant and according to them the Rs have updated/different timing chains and chain tensioners. Thus needing two different long blocks and frpp does sell both parts btw

Gogoggansgo · Jun 29, 2018

jvandy50 · Jun 29, 2018

whaaaaat?? so that was NOT a part number listed by mistake?

i mean, i still ain't gettin it, but it's interesting to say the least

AustinSN · Jun 29, 2018

Hmmmm.

I'd like some more clarification on that other than the one FP website. Looking at some of the parts websites it lists the timing chains and guides as the same between the R and non R.

Unless the websites aren't that comprehensive and we need to look at a book..

@FORDSVTPARTS any help?

JAJ · Jun 29, 2018

That picture is out of date. The Ford Performance website now says:

"Upgrade the primary timing chains of your 5.0L Coyote engine by swapping them out for the GT350 5.2L primary timing chains! These chains offer 10% greater strength over 5.0L Coyote timing chains. Oriented for racing applications.

-Fits 2015-2017 Mustang GT 5.0L

-Original equipment on 2015-2018 Mustang GT350 and GT350R 5.2L

Includes:

Set of 2- GT350 primary timing chains"

AustinSN · Jun 29, 2018

The man speaks the truth

Gogoggansgo · Jun 29, 2018

It still doesn’t explain why there is two different long blocks. I know how ford is with money so i can guarantee you that’s its something small but enough to warrant a different part number.

Gogoggansgo · Jun 29, 2018

JAJ said:
That picture is out of date. The Ford Performance website now says:

"Upgrade the primary timing chains of your 5.0L Coyote engine by swapping them out for the GT350 5.2L primary timing chains! These chains offer 10% greater strength over 5.0L Coyote timing chains. Oriented for racing applications.

-Fits 2015-2017 Mustang GT 5.0L

-Original equipment on 2015-2018 Mustang GT350 and GT350R 5.2L

Includes:

Set of 2- GT350 primary timing chains"

I know it’s out of date but this isn’t the first time ford racing has changed info on part due too people complaining. When word got out about that timing chain bs. It was a firestorm and i know they changed the info right afterwards. So at this point i don’t know what to tell anyone other than the R owners aren’t getting another 25hp over the gt350 guys .

Tob · Jun 30, 2018

Gogoggansgo said:
I know it’s out of date but this isn’t the first time ford racing has changed info on part due too people complaining. When word got out about that timing chain bs. It was a firestorm and i know they changed the info right afterwards.

Rather disingenuous to post prior to the above an old link image that was in error. Now you admit that you knew it was out of date. It wasn't changed due to people complaining but rather people pointing out to Ford Racing that the listing was wrong. I was one of them and sent emails to those that I know there almost immediately upon seeing the mistake they had made.

And yes, the resonators add restriction. A small amount in the case of the GT350 system but a restriction nonetheless.

GT350 vs GT350R Engine Differences?

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