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GT350 manifold worth it?

Bluemustang

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I'm toying with the idea of getting a GT350 intake manifold and 47lb injectors. But my car is an auto and I'm not going to get headers due to emissions reasons (I live in Maryland where they enforce it).

Right now all I have is a JLT CAI w/ paper filter and Lund FF running E85. But if I get the manifold and want to continue using E85 I need bigger injectors.

Is the power increase worth it in your opinions? How many RWHP would I be looking at with CAI/GT350 mani/injectors/E85?

I saw this guy Alejandro Flores on YouTube got 430 RWHP on headers/CAI/GT350 mani and pump gas- on an automatic car, which mine also is. Considering I'm without headers and E85 adds probably 10 WHP I'm thinking that I'd be right around 430 as well? Or no?
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Taneras

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I'm toying with the idea of getting a GT350 intake manifold and 47lb injectors. But my car is an auto and I'm not going to get headers due to emissions reasons (I live in Maryland where they enforce it).

Right now all I have is a JLT CAI w/ paper filter and Lund FF running E85. But if I get the manifold and want to continue using E85 I need bigger injectors.

Is the power increase worth it in your opinions? How many RWHP would I be looking at with CAI/GT350 mani/injectors/E85?

I saw this guy Alejandro Flores on YouTube got 430 RWHP on headers/CAI/GT350 mani and pump gas- on an automatic car, which mine also is. Considering I'm without headers and E85 adds probably 10 WHP I'm thinking that I'd be right around 430 as well? Or no?
http://www.mustang6g.com/forums/showthread.php?t=41371

This thread should give you a decent idea of what to expect.

Only two differences between you and their build, they installed a GT350 throttle body and they used 93 octane fuel. I don't think the GT350 throttle body did much. I'm planning on doing what you're doing (but I do have catless LT's) and I'm confident its a good investment.

As far as the guy on YouTube, I'd venture to say that LT's when combined with a GT350 manifold would be a bigger boost to hp than switching from 93 octane to E85. In other words, I'd expect him to put out slightly higher numbers.
 
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Bluemustang

Bluemustang

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My goal is to reach 500 crank horsepower. If I could do that I think it would be worth it. Plus the ability to rev higher would make things easier with the extremely short first gear in the 6R80 transmission.
 

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IMO the GT350 manifold is the best upgrade for the 2015+ Mustang GTs.
As long as you keep the CMCV.. if ya don't it'll be a dog under 5k rpm.
The BOSS & COBRA JET give up too much low/mid range for the street
I think. Just my humble 2 cents.
 

Taneras

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As long as you keep the CMCV.. if ya don't it'll be a dog under 5k rpm.
Interested about this, by any chance have you come across any dynos that did a test between the CMCV plates and the delete? Just curious as to how much low end you're sacrificing to get a better gain up top - because that's essentially what the GT350 manifold is doing based on all the dynos I've seen. What do you think most people end up doing?

As for the OP, I think its fair to say you'd hit 500 crank hp if you have an E85 tune with an intake and GT500 manifold. Hitting the 425/430rwhp mark puts you right around that. It would depend upon the dyno and the air quality.
 

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WildHorse

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What do you think most people end up doing?
Dunno. But I've dyno tests on the stock GT IM with CMCV intact and some VCT tuning and your cooking to 7500 rpm. Locked out CMCV your losing torque under 5k bigtime. Lock out cams losing something like 120hp in the mid rpm's. Seems the higher the revs.. the more the slight restriction with the CMCV comes into play. Stock GT manifold can be revved to 7500 rpm.

IIRC one of the Ford magazines did a test.
 

V8EATR

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I think its worth it. Back to back at the drag strip I had good gains. With the GT350 mani, the car was 80lbs lighter but It picked up .15 and 3mph and the DA was almost 1500' higher.
 

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Its worth it. The car keeps pulling to 8k rpm instead of falling off after 6500rpm. You will pick up about 20-30whp at peak and nearly 50whp above 6500rpm. As long as you will rev it that high you will love the gains. If not the stock IM is still capable of hitting 430whp with cat deletes.
 

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If no headers.......... well that's the reason I haven't done it (that and cost). Know a few people now with the GT350 manifold AND headers and their car is notably faster. I can't justify it without headers, personally, and those make the car way too damn loud unless you strap on a row of exhaust parts that end up weighing as much as the stock exhaust.

I'm looking forward to more results from the 2015 F150 manifold testing happening by a few folks. Midrange seems to be helped out, which is what I care about most. No plans to go to 8,000 RPM here.
 

ALUSA

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IMO the GT350 manifold is the best upgrade for the 2015+ Mustang GTs.
As long as you keep the CMCV.. if ya don't it'll be a dog under 5k rpm.
The BOSS & COBRA JET give up too much low/mid range for the street
I think. Just my humble 2 cents.
Nope, the Cobra Jet gives the best low and midrange torque out of all of them. The only problem is the hood clearance and tuning for mono or single blade with intake. There has been comparisons done on reputable websites. Cobra Jet infact gives more low and midrange than a stock im, plus better than gt350 on top.
 

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TooSoonJunior

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No, please don't try to rev the stock intake manifold to 7500rpms, lol. Yes itll make it there, NO it is not making more power or going faster than if you just shifted it at 7000 and use the higher torque in the next gear

Cobra Jet and GT350 are within spitting distance of each other in all ways. The only dynos out there comparing the two are WITHOUT full cam timing tunes for the GT350. With that tuning, the torque loss is near non-existent. Yes, Cobra Jet flows more past 7,000rpms. Not a TON, but yes it does. IT WILL NOT likely flow any better than the GT350 without headers, both setups will suffer past 6500rpms on stock headers.

The downsides of the CJ manifold is fitment and tuning side. There are 4 options today for a tune for the GT350 manifold that will 100% drive like stock (FRPP, Lund, AED, HP Tuners [yes the FRPP tune is out there to download and use]). For me, that means a lot, and would prefer the GT350 setup.

I have never tried to install or use a CJ setup, so take it for what its worth. I installed a full GT350 setup (manifold, cold air, throttle body), loaded a HP Tuner tune, and was out beating the snot out of it in under 3 hours.

If interested I am considering selling my GT350 setup, shoot me a PM.
 

wildcatgoal

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Nope, the Cobra Jet gives the best low and midrange torque out of all of them. The only problem is the hood clearance and tuning for mono or single blade with intake. There has been comparisons done on reputable websites. Cobra Jet infact gives more low and midrange than a stock im, plus better than gt350 on top.
This is true. I've seen back to back GT350 vs. CJ manifold drag races (at strips) and the CJ wins in trap speed and time just about every time, unless the guy has a bad launch. Typically we're talkin' street tire runs. I haven't seen every race of the GT350 vs. CJ and #drivermod matters but... then we have dyno days relatively often and, well, the CJ wins by a smidge again in the curve.

The GT350, compared to the CJ (if you're going to change the manifold anyway), is a much better bang for the buck, though. I think the CJ, because of the fancy TB and need for at least a different intake tube, is notably more expensive.
 

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IMO the GT350 manifold is the best upgrade for the 2015+ Mustang GTs.
As long as you keep the CMCV.. if ya don't it'll be a dog under 5k rpm.
The BOSS & COBRA JET give up too much low/mid range for the street
I think. Just my humble 2 cents.

I don't know how true that is with the Boss. I can blow my tires off through three gears. I think I need to get my car on my dyno. It feels loads better with the Boss and new lund tune than it did with the OE intake manifold. And it sings a very loud melody all the way to 7,800 rpm fuel cut that is in my tune.
 

HISSMAN

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A lot of people have done better than that with the BOSS when the tune is customized for it. That is an oldie and was just a basic swap and go. No real tuning was done to maximize on each manifold.
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