GT350 VS 18 Intake Manifolds

armykyle1

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If you get the 18 mani, don't buy lock outs, just use zip ties.

I had a GT350 mani on my 2015 GTPP and loved it. Easily my favorite mod, especially with the 3.73s making you shift all the time.

Also, you don't need to delete IMRC functionality with the GT350 mani on a 15-17. So torque loss down low can be minimal. Don't let your tuner be lazy. I got my GT350 mani and TB for $650 used.


Either one you opt for, ditch the air raid, get a pmas or jlt(if you go jlt, get the GT350 option)



I have spoken.





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TeamDenno

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I'm late to this discussion.

As a direct comparison, I have an 18 Mani on a 17 car, a mate has the GT350 Mani and GT350 TB on his 17.

We both have 1 7/8ths headers (one XForce one American Racing). Both running E85. One tuned ny Lund (me) and one tuned by PB.

The Lund Tuned 18 Mani hit 448hp at the wheels
The PB Tuned GT350 Mani hit 441hp at the wheels

The runs were on the same dyno, same day half an hour apart at approx the same temp.

Similar results on the max torque - I was slightly higher all the way thru the rev curve.

The 18 Mani revs higher. (8350 vs about 8000)

The GT350 Mani hardware setup was about 4x times the cost of the 18 Mani setup.
18 Mani has IMRC locked out.

Take this for what its worth.
 

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armykyle1

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I'm late to this discussion.

As a direct comparison, I have an 18 Mani on a 17 car, a mate has the GT350 Mani and GT350 TB on his 17.

We both have 1 7/8ths headers (one XForce one American Racing). Both running E85. One tuned ny Lund (me) and one tuned by PB.

The Lund Tuned 18 Mani hit 448hp at the wheels
The PB Tuned GT350 Mani hit 441hp at the wheels

The runs were on the same dyno, same day half an hour apart at approx the same temp.

Similar results on the max torque - I was slightly higher all the way thru the rev curve.

The 18 Mani revs higher. (8350 vs about 8000)

The GT350 Mani hardware setup was about 4x times the cost of the 18 Mani setup.
18 Mani has IMRC locked out.

Take this for what its worth.
You're flat retarded running a 18+ mani to 8300. The manifold doesn't "Rev". That's set by the tune. I'd love to see a Lund tune with 8300rpm with a 18+ mani 😂😂😂. Secondly, the 18+ falls off faster and sooner than a GT350 mani.
 

Zelek

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You're flat retarded running a 18+ mani to 8300. The manifold doesn't "Rev". That's set by the tune. I'd love to see a Lund tune with 8300rpm with a 18+ mani 😂😂😂. Secondly, the 18+ falls off faster and sooner than a GT350 mani.
Lund set my soft redline at 7900 and my hard redline at 8200. It's meant to be that way so you aren't bouncing off the rev limiter and break your OPG's. To your point, it's not good to go much past 7500-7600 on the 18 manifold. You're better off with a GT350 manifold at that point and might want to be looking at cams to make use of actual power at that rpm.
 

Knexo

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I can attest that the 18 mani fold is well worth it. Unless your looking for maximum HP, get it ported isn't worth the money in my opinion. I'm not chasing a maximum number. I just wanted to wake the car up above 3000rpms. I agree with what someone said earlier also about get rid of the airraid. I personally went with the Steeda open, but again the PMAS or JLT are just as good. I would also recommend getting atlelast 47# injectors. Even if you don' want to run e85 now, you might in the future and its good protection also.

If you have an auto car with 3.15 gears, your going to be disappointed with the low torque loss if you do the lock outs. I have lock outs right now and I'm thinking about going back to them or changing to a 3.55 gear.

Set Up - 18mani-47# inj-Steeda Open CAI-Ngauge E85 Flex tune PB-7400RPM

The rush is like having a new car again so you can't go wrong doing either of them.
 

ZenkaiRacer

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Does anyone have the 18 mani swap with the IMRC's working right on a 15-17? When I first started looking into this swap I saw that the pigtails were available and just assumed if those existed it would work?
 

Zelek

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Does anyone have the 18 mani swap with the IMRC's working right on a 15-17? When I first started looking into this swap I saw that the pigtails were available and just assumed if those existed it would work?
It's a 50/50. Some are successful, some have issues. If you ever plan on forced induction later, just lock them out now.
 

TeamDenno

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I can attest that the 18 mani fold is well worth it. Unless your looking for maximum HP, get it ported isn't worth the money in my opinion. I'm not chasing a maximum number. I just wanted to wake the car up above 3000rpms. I agree with what someone said earlier also about get rid of the airraid. I personally went with the Steeda open, but again the PMAS or JLT are just as good. I would also recommend getting atlelast 47# injectors. Even if you don' want to run e85 now, you might in the future and its good protection also.

If you have an auto car with 3.15 gears, your going to be disappointed with the low torque loss if you do the lock outs. I have lock outs right now and I'm thinking about going back to them or changing to a 3.55 gear.

Set Up - 18mani-47# inj-Steeda Open CAI-Ngauge E85 Flex tune PB-7400RPM

The rush is like having a new car again so you can't go wrong doing either of them.
Mine isnt ported and was considering getting it ported. Its worth somewhere between 7-20Hp apparently (according to the local tune place - and they said they payoff wasnt worth it).

I am on a 6MT at 3.55 (standard on our Aussie cars) and was considering 3.73's - but my tyre guy who is also my suspension guy said one of his other clients cars didnt make that much change from 3.55 to 3.73!

Yes to the 47# injectors. And I do run E85 - especially at the track. Wakes the beast right up.
 

Jackson1320

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I got my ported 18 manifold for $300 and you don’t need lockouts just zip ties but if you do want them they are $20. How is that anywhere near a gt350
 

Jackson1320

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I can attest that the 18 mani fold is well worth it. Unless your looking for maximum HP, get it ported isn't worth the money in my opinion. I'm not chasing a maximum number. I just wanted to wake the car up above 3000rpms. I agree with what someone said earlier also about get rid of the airraid. I personally went with the Steeda open, but again the PMAS or JLT are just as good. I would also recommend getting atlelast 47# injectors. Even if you don' want to run e85 now, you might in the future and its good protection also.

If you have an auto car with 3.15 gears, your going to be disappointed with the low torque loss if you do the lock outs. I have lock outs right now and I'm thinking about going back to them or changing to a 3.55 gear.

Set Up - 18mani-47# inj-Steeda Open CAI-Ngauge E85 Flex tune PB-7400RPM

The rush is like having a new car again so you can't go wrong doing either of them.
I had a ported 18 manifold with auto and 3.15 gears and lockouts. dyno showed 5tq lose. Nothing you will notice
 

TX5OH

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I have a GT350 intake manifold waiting to go on my 2016. But the TB adapter is lost in transit or so it seems. FedEx has shown pending and in Memphis since last Friday. Ugh!!
 

Knexo

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I had a ported 18 manifold with auto and 3.15 gears and lockouts. dyno showed 5tq lose. Nothing you will notice
That’s why I’m saying it’s not worth the money to port them. If your someone that needs to chase a maximum dyno number, then spend the money. 5 ft lbs is a 10mph crosswind breeze at the track. You aren‘t going to notice it.

I’m hoping the 3.55 gears just get the car in to the higher RPM‘s faster, that’s all. Lowers gears will always make a vehicle feel faster because of that reason.
 

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