Boss Manifold Tuning *Dyno Inside*

[dev1360]

Stock intake falls off hard 6,400-6,800. I have swept the cams on a dyno with the stock intake and there is no power to be found above that with the stock intake. By 7,200-7,300 RPM it has taken a full dive off a cliff and it is making very little power.

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[Silver50Pony]

Stock intake falls off hard 6,400-6,800. I have swept the cams on a dyno with the stock intake and there is no power to be found above that with the stock intake. By 7,200-7,300 RPM it has taken a full dive off a cliff and it is making very little power.

Ask Iketh he's making power well into 7000+ rpm and shifting 7800 with stock manifold, ran 11.9 at 119 long tubes and catback street tires

 

[dev1360]

I'd like to see dyno sheets from a correctly calibrated dyno with that. My car fell off at 6,400 like the power curve had an anchor on it.

I also went 11.9x and trapped 119.8 on the stock intake shifting at 6,900RPM. So if he is making power for another 800RPMs than every other stock intake on every other S550, it's not doing anything for him.

 

[WildHorse]

Peak Torque (Lb-ft) 400 @ 4250rpm
Peak Power (Hp) 435 @ 6500rpm
Maximum RPM 7,000

Soooooo the stock intake can't drop like an anchor at 6400 cause the hp peak is at
6500. Even after that, I've never ever seen any intake 'drop off a cliff' for another 300rpm past peak HP. Heck, even 2bbl carbs on stock cast iron manifolds on dirt track racers make power to 7500+. JMHO.

 

[V8EATR]

Peak Torque (Lb-ft) 400 @ 4250rpm
Peak Power (Hp) 435 @ 6500rpm
Maximum RPM 7,000

Soooooo the stock intake can't drop like an anchor at 6400 cause the hp peak is at
6500. Even after that, I've never ever seen any intake 'drop off a cliff' for another 300rpm past peak HP. Heck, even 2bbl carbs on stock cast iron manifolds on dirt track racers make power to 7500+. JMHO.

Have you ever seen a dyno of a Coyote with a stock intake? NA they all look the same. Peak 65-6700 and downhill after that. The length of the runners is the problem. It doesn't matter what you do with the VCT or fueling.

 

[dev1360]

It's a physical limitation of the intake design. Period. People can wish and hope all they want. The intake is not physically capable of making power that high.

 

[HISSMAN]

It's a physical limitation of the intake design. Period. People can wish and hope all they want. The intake is not physically capable of making power that high.

This. The intake is not designed to flow air correctly on this engine and continue to make power beyond around 6,500-6,800 rpm. Change the cams, change the filter...it doesn't matter.

 

[WildHorse]

Not wishing or hoping. BUT I'm betting there's something else at play here on a stock tune. Fuel/timing/both. The stock intake is more then capable of flowing the required air.

I'll have to look into it further, thanks

 

[dev1360]

I have personally swept intake and exhaust cams through their ranges of motion on a dyno for several hours. Every cam angle, different timing and fueling. It will not make power above its physically designed range.

Runner length, plenum size, and the resulting secondary pulse waves dictate an efficiency range. The stock intake makes strong HP and Torque from about 5,200 to 6,400, sometimes reaching 1.1 air load from the secondary pulse wave supercharging. But once it's done, it is done. And done hard.

 

[HISSMAN]

I've been balls out with the stock intake and never made power above 6,700. It always dropped like a rock. VCT tuning, E85, etc, etc. It comes down to volumetric efficiency.

 

[WildHorse]

@dev360 BOSS it is then. Thanks for the detailed answer

 

[V8EATR]

Not wishing or hoping. BUT I'm betting there's something else at play here on a stock tune. Fuel/timing/both. The stock intake is more then capable of flowing the required air.

I'll have to look into it further, thanks

So if you put a 55 gallon drum on your heads it should be rev to 1,000,000? The size of the plenum doesn't make the difference in RPM.

 

[kris5597]

I have personally swept intake and exhaust cams through their ranges of motion on a dyno for several hours. Every cam angle, different timing and fueling. It will not make power above its physically designed range.

Runner length, plenum size, and the resulting secondary pulse waves dictate an efficiency range. The stock intake makes strong HP and Torque from about 5,200 to 6,400, sometimes reaching 1.1 air load from the secondary pulse wave supercharging. But once it's done, it is done. And done hard.

I've been balls out with the stock intake and never made power above 6,700. It always dropped like a rock. VCT tuning, E85, etc, etc. It comes down to volumetric efficiency.

I too have spent countless hours tuning every VCT angle the camshafts will allow in 5 degree increments to see how much I can really push out of the stock intake manifold, even with every restriction before the intake manifold and after the heads eliminated/ reduced and the highest rpm I could achieve was around 6500-6600rpm peak power, after that power falls off. You can safely rev to 7000-7200 rpm without too much negative effect of falling out of the power range but that is absolute max.

I also did the same tuning sitting with the Boss manifold to maximize VE at all rpms. There was power to be made for sure, peak power was around 7700-7800 with the boss, however with the design of the boss compared to the stock intake manifold, torque/ hp was lost down low but everything above 6000rpm was very solid gains, revving the car to 8100rpm. Flow numbers were drastically improved over the stock intake manifold. All of this data was already mentioned in previous posts.

~Kris

 

[WildHorse]

Pretty good write up on aftermarket cams + GT/BOSS/FORD RACING intakes vs Comp cams + GT/BOSS/FORD RACING intakes.:

http://www.mustangandfords.com/how-...fb_social_M360_170803_sf103553952#sf103553952

The FORD RACING intake has some interesting #'s. So does the GT intake w/ comp cams.

 

[kris5597]

Pretty good write up on aftermarket cams + GT/BOSS/FORD RACING intakes vs Comp cams + GT/BOSS/FORD RACING intakes.:

http://www.mustangandfords.com/how-...fb_social_M360_170803_sf103553952#sf103553952

The FORD RACING intake has some interesting #'s. So does the GT intake w/ comp cams.

That is the best information I have seen to date, and speaks the truth. Further proves the Boss manifold is in fact an upgrade as I have been preaching for years. Also shows that yes, the CJ is an upgrade, but hp per dollar, the Boss trumps it. Also proves that a good set of cams tuned properly will allow all manifolds to really wake up, but again, shows the benefits of having a manifold targeted for higher rpm to really allow the heads of the coyote to shine. Thanks for sharing this.

Kris

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