15-17 intake manifold improvements?

[Jay-rod427]

Best mod for a 15-17 manifold. Take it off, set it upside down on your work bench, take a 10 lb sledgehammer to it so the smaller pieces fit in the trash can better.

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[WildHorse]

What would be nice is one that corrected the angle on the 18+ manifold.

If I had a 18 manny.. We'll try it out on my 17. But I'm sure the face can be at whatever angle.

 

[1MeanZ]

Got a 1500 mile stock Gen2 intake from a member here. Will be delivered tomorrow. Going to see if I can get it on my buddies flow bench and see what it does stock, port it and flow it again, then put it on the car and see what happens. Stay tuned...

 

[WildHorse]

Going to see if I can get it on my buddies flow bench

FINALLY some smart cookie is gonna do the smart thing. You'll be super pleased with the end result ;)

 

[1MeanZ]

FINALLY some smart cookie is gonna do the smart thing. You'll be super pleased with the end result ;)

I hope so! Many of us would like to keep the mid-range power and torque of the Gen 2 manifold and just minimize the power drop from 6500-7k. If I can extend the power a little flatter for just another 500rpm, it's a huge win for Gen 2 guys. We can port the original manifolds and not have to re-tune, keep the stock engine cover, keep the stock IMRC setup, vacuum line routing etc.

 

[Nuked]

I hope so! Many of us would like to keep the mid-range power and torque of the Gen 2 manifold and just minimize the power drop from 6500-7k. If I can extend the power a little flatter for just another 500rpm, it's a huge win for Gen 2 guys. We can port the original manifolds and not have to re-tune, keep the stock engine cover, keep the stock IMRC setup, vacuum line routing etc.

Be interesting to see what you find. My 15-17 been sitting in storage for 2 years, so if porting it is something worthwhile that be a great winter project.

 

[WildHorse]

Well the stock 15-17 GT manifold MURDERS all other intakes up to 6500 rpm. Don't know anybody who cruises at 7000 rpm. Cept those honda vtecs with ginormous fart cans yo.

 

[DonnieO]

I'm deff watching this thread!

 

[Nuked]

Well the stock 15-17 GT manifold MURDERS all other intakes up to 6500 rpm. Don't know anybody who cruises at 7000 rpm. Cept those honda vtecs with ginormous fart cans yo.

That is where you need to take gearing into consideration. My thought process is that a 3.73 MT car benefits more from the 18+ over the 15-17 simply because of where the rpm drop on the shift goes.

 

[80FoxCoupe]

Yeah you would have to figure something out there. I thought about the TB spacer as well, my biggest question though was if it works why hasn't anyone made one? TB spacer isn't rocket science, I agree with you on it adding plenum volume, I just wonder why it hasn't been done.

Engine Masters have proved that increased plenum volume on an MPFI engine doesn't really do anything. Runner length and cross section are the determining factors.

 

[1MeanZ]

Engine Masters have proved that increased plenum volume on an MPFI engine doesn't really do anything. Runner length and cross section are the determining factors.

You are correct, I stated earlier that i'm likely not going to be able to actually shift the point of peak power because I can't really change the runner length. Also discouraging is the fact that the ramp up to peak power and the drop off after peak power appear to be similar slopes. I would have thought that if there was a flow restriction, the power would drop off quicker? Not sure. At any rate, as stated, if I can flatten the power drop off after 6500 it's a win. More likely possibility is that if I can increase flow, the curve will be identical and it will still drop off after 6500 due to resonant tuning losses, but I'll be up a few hp/tq everywhere, basically just shifting the exact same curve up 5-10hp. The most likely scenario is that I A: can't get enough of a gain on the flow bench with porting B: even if I do get a gain it won't translate into power.

I expect that i'm wasting my time, but there is just no data on the Gen 2 manifold out there. So we have to explore and see if there's any power hiding that no one has found yet.

 

[80FoxCoupe]

Just get a supercharger!

 

[WildHorse]

I expect that i'm wasting my time, but there is just no data on the Gen 2 manifold out there. So we have to explore and see if there's any power hiding that no one has found yet.

Sorry to hear that. Add volume, port it, boom as good as an 18+ intake that'll rev still the stock cam roll over.

 

[TeamDenno]

Anyone that's looked at the power curves of the stock 15-17 manifold vs the '18+ or GT350 manifolds can see that the 15-17 intake is better until 6500rpm. I think the ideal scenario for many of us with street cars would be to find a way to port the 15-17 manifold to get another 500+rpm out of it. If you could get the 15-17 manifold to make equal power to the 18 manifold at 7000 rpm but still make more power down low that would be the win-win in my opinion.

So the question is, does anyone know in detail the shortcoming of the 15-17 manifold? Is it runner length too long? Can it be ported? I've looked everywhere and I can't find anything on modifying a 15-17 manifold, everyone dumps them for the 18+ or GT350. If anyone has a 15-17 manifold they want rid of, PM me and I'll pay shipping. I'd like to try to modify one and see what happens...

Once you have tuned your engine to suit the '18 mani on a 17 Coyote, you dont notice the near negligible loss of torque.

What you do notice is the extra oomph you get when pushing the car hard around tight and twisty roads and out on the track. Thats where the 18 comes into its own

 

[1TUFF_S550]

Exactly. When i had the ported 18 on my 17 with the IMRCs locked out, it felt stronger throughout the whole rpm band. Regardless if it was wot or just tip in throttle to pass up a car. Other “mods” were 47lb injectors, mishimoto tube with k&n filter stock box, xpipe nd roush axleback. And it was running on a base tune from shaun. Didnt get a chance to tune it on the e85.

Once you have tuned your engine to suit the '18 mani on a 17 Coyote, you dont notice the near negligible loss of torque.

What you do notice is the extra oomph you get when pushing the car hard around tight and twisty roads and out on the track. Thats where the 18 comes into its own

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