would the GT intake work better on a BOSS engine? lets find out!

pufferfish

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the car: 2011 brembo GT, 3.55 gears
the engine: parts bin build factory boss engine with upgraded cj pulse ring, billet oil pump gears, C&L cold air, OE throttle body
ancilliary mods: kooks shortys, bbk cat deletes, gt500 mufflers, spec stage 1 clutch and aluminum flywheel, dynotech aluminum driveshaft
the tune: Adam from Revolution Auto in Rosedale, MD on a DynoJet

First, thanks Adam and crew for the most extensive dyno session i have ever witnessed! Adam perfected the tune for both the gt and boss intakes on this engine.

They had issues maxing out the MPH on the dyno in 5th gear above 7500, so I have 4th gear pulls for both manifolds as well as 5th.

5th gear GT:428/413, BOSS:426/388
4th gear GT:430/396, BOSS:441/377

the GT and BOSS were even from 2200-3000
the GT had the BOSS from 3000-5600
the GT and BOSS were even again from 5600-6600
the GT fell off after that and the BOSS held pretty steady, but showed a small hump peaking at 7600 and continued to make great power to 8200

what is clear to me is the boss mani works much better with the boss motor than the gt motor. what is also clear to me from looking at tuned coyotes is that the gt intake doesn't drop off as dramatically after peak on top of a boss engine as it does on a coyote motor. i think the gt is a solid contender for supremacy on top of a boss engine! it doesn't peak as well, but the power throughout the curve is better or equal up to 6600.

what do you think?

y3cd.jpg


wlrk.jpg
 

pufferfish

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thanks for your input, but there's no reason to be so brash and I do feel this is the correct forum since ITS A BOSS ENGINE. I just wanted to share my empirical data on a subject that has been quietly mulling about in performance shops across the country.

Boss purists feel free to quietly ignore this thread.
 

86Fbody

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Oh snap thread Nazi, next we won't be allowed to post in other sections if we don't own the applicable model/year. What did the AF mixture look like for each? Did they have to correct with adding more fuel to one intake or the other?
 

pufferfish

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AF is shown in the lower graph in each dyno sheet. it was rock steady at what looks to be somewhere between 12-12.5:1. I can't say what was changed, but the tunes were totally different. different fuel, timing and VCT.
 

86Fbody

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Understandable that the tunes would be different. Just wondering other the the extra 500 rpm what the advantage of the Boss intake is.
 

pufferfish

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its not just an additional 500 rpm. it carries hp within 15 of max from 6700 all the way to 8200. that is an impressively flat curve (lust looking at that section)!

i'm not knocking the boss intake. it is very good at doing what it was intended to do....bring the rpm range up. its just interesting to see that the gt intake is pretty awesome with the right engine under it. the comparison is intended to show where each intake excels and lacks to help people decide which works best for their intended use.

street, the gt is unbeatable. torque rules the stoplights, period.
drag, boy I don't know, but intend to find out soon!
track, that, more than even drag, is dependent on gear ratio. the boss would be insane with some 4.10's. with my 3.55's, the gt is a better choice for me.
 

pufferfish

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Good solid test. How much more does a boss engine (heads) flow then a stock GT?

well, I tried to find flow data before making my final decision to use boss heads in my build, but there is just nothing out there. in a mag article about the boss engine, a ford engineer stated that the intake flows 6% more than gt heads and 10% more on the exhaust. if those numbers are right, they are a bit less than the flow of all the ported head contenders on the market. my decision came down to construction and port volumes. ported heads use gt valves (and some have larger solid ss valves), where the boss heads use hollow stems and sodium filled. the boss heads are cast from a stronger aluminum (rumored to be the same material used in the powerstroke heads) and they are cast with smaller ports, so when they cnc the runners, the net volume matches the gt heads. this is something no ported head can achieve. bigger port volumes reduce velocity, which is a friend to NA motors. in my opinion, for a milder NA build, the boss heads are the best. monster NA builds are probably better on ported heads. forced induction is definitely better with as large a port volume as you can get.
 

Ultrakla$$ic

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5th gear GT:428/413, BOSS:426/388
4th gear GT:430/396, BOSS:441/377

With these numbers I'd rather have the TQ advantage of the GT. If only the stock manifold wasn't so ugly!:D

Thanks for posting!
 

pufferfish

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I know, right! The boss mani just looks so good!...and the gt, well, it's definitely "function" over "form".
 

EJR

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Good comparison. But at the end of the day... RPM is king.
 

isrboss

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Good comparison, but not a serious one. The intakes are clearly engineered to perform in a certain rev range, short vs long runners. If you have the ability/build to rev up to 8000+rpm, you would be a fool to prefer an intake (GT) that is only able to keep up with flow up to 6800rpm. The good old text of "you have to give a little to get a little". A well driven Boss will make great use of that flat HP up top on a road course, and most likely a drag strip. Back in my S2000 days the difference in a good lap and a F'n crazy fast lap was the driver basically beating the motor to what we felt was it's life end. If you like to lug around the road course and don't like to shift much, a GT is for you. Not the GT intake, the GT.
 

86Fbody

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Good comparison, but not a serious one. The intakes are clearly engineered to perform in a certain rev range, short vs long runners. If you have the ability/build to rev up to 8000+rpm, you would be a fool to prefer an intake (GT) that is only able to keep up with flow up to 6800rpm. The good old text of "you have to give a little to get a little". A well driven Boss will make great use of that flat HP up top on a road course, and most likely a drag strip. Back in my S2000 days the difference in a good lap and a F'n crazy fast lap was the driver basically beating the motor to what we felt was it's life end. If you like to lug around the road course and don't like to shift much, a GT is for you. Not the GT intake, the GT.

You can't entirely compare one car to another, also can't say that RPM is King.
 

EJR

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Tell that to the 8400rpm V8 powered M3 guys getting stomped on!

Id rather make 1500rpm of peak power and sit in that range the entire time then make 300rpm of peak power and shift out of it in each gear...
 

isrboss

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You can't entirely compare one car to another, also can't say that RPM is King.

I don't know what you are even saying here. If I'm still pedal to the floor and you're shifting to a lower rpm that produces less power, there is no comparison, I'm going you're not. The variables get sloppy when posters compare how many M3's they passed on track during a HPDE. That is were you cannot compare one car to another due to driver. The M3 is a bad ass car and many are not driven well, because you have got to keep it up top. Not everyone has the stomach for that. I would enjoy nothing more than getting one just to pass Boss 302's on track. I'm a car guy not a brand guy.
 

EJR

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Bottom line is this... when i shift at 8k... I come back into the next gear making the same power I did when i left the previous gear. Between that, the MT82 gearing, and 3.90s... I could careless about that low end tq number.
 

86Fbody

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I don't know what you are even saying here. If I'm still pedal to the floor and you're shifting to a lower rpm that produces less power, there is no comparison, I'm going you're not. The variables get sloppy when posters compare how many M3's they passed on track during a HPDE. That is were you cannot compare one car to another due to driver. The M3 is a bad ass car and many are not driven well, because you have got to keep it up top. Not everyone has the stomach for that. I would enjoy nothing more than getting one just to pass Boss 302's on track. I'm a car guy not a brand guy.

I'm saying you cannot compare the way you drive an S2K to a Mustang, and if RPM is king then how is the Mazda Skyactiv-D competitive at all?
 

isrboss

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I used the S2000 as a reference because it makes it's power up top, similar to a Boss motor. Of course the Boss still make great power throughout the power curve, but you are not going to help your lap times lugging the Boss around the track. It's harder to hide mistakes on track with lower torque and making power up top.
 

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