Imo000

Mark,
This is going to go sideways soon!

V2Rocket

i have no doubt that your experience, research and math would make a better intake for your (and your customers') purposes than say building an LT1-lookalike intake to suit a 928.
just that while resonance tuning is a cool thing to use (if you can fit it), it's not going to make or break the driveability of an engine, just alter its characteristics.

if torque is king, build a 928-TPI intake...

Mongo

Torque is king on roads. Track tends to negate that depending on the circuit.

mark kibort

Nah, i wont let it. im just trying to help.....im not going to push it any harder. i get where greg is coming from. it certainly makes sense and he does make the most well thought out components .
I just am trying to add real world application to logic of the design. in other words, if we are talking automatics.... he has a HUGE point.

I guess it depends on what you mean by "king on the roads". Its king, if you dont want or can downshift... or are driving an automatic.
the gears are torque and HP optimizers (for rear wheel forces) so, find the right gear that gives the most amount of HP at that speed, and you will have the most acceleration forces. ( this is regardless of comparative torque levels.)

Mongo

I am driving an automatic. And, my car is road use only as I am handicapped by stoplights and signs in suburban hell. Nothing against HP, but a manifold that yields even numbers and better ones than the factory benefits most streetable 5.0 928s out there. Also, no one has really answered why the 'spider' was such a bad intake? One can be made out of sheet metal with sufficient runner length, compact? I don't know, I'm not a metal fabricator.

I've also paid more attention to Mercedes engine designs lately; they have V8s with great torque figures, pre-turbo. Look at the M156 AMG engine that you find in the C63 and E63. Just tons of torque and HP, and 32 valves to boot. Intake manifolds are well-engineered, but by god do they make use of those little flappies to tune the runners!

Corvettes.... simplest manifold on the LS, oodles of torque like a Mercedes.

mark kibort

Andy, you just hit the nail on the head with this post. automatics are majorly hurt by engine HP lying in the max RPM range. however, recently with 8 speed transmissions, etc, this issue of requiring "lower RPM available HP" is getting less and less. go drive an 8speed BMW 640i and you will see what i mean. very little "torque" but HUGE fun and great power from the moment you push the gas at any speed. why? because it puts the RPM in the max HP range for best acceleration, and has different settings of how aggressive it will be as well. in the "race mode" it is almost like driving a GT3 cup car paddle shifter with a auto-blipper for downshifts!
so yes, if you have a wide spaced gear box, and few gears, there is absolutely gains on the street by using a well designed intake that raises lower RPM HP levels.

Mongo

I have 2 Mercedes with 5 speed autos and 1 with a 7 speed (E350). The E350 can easily embarrass my car whether it has the x-pipe and EZK chip or not. The CLK feels just as fast as the 928 but my wife still laid waste to me in her E. Moral of the story.... just throw more gears at the engine


On a side note, I drove a P31 (AMG Development Package) equipped C63 Coupe. That car is next on the list for purchase. Especially after seeing what Eurocharged has unlocked in that ECU as far as power gains (see mbworld.org) That C63 is a total sleeper car and an awesome modding platform too. Tons of torque, tons of grinning too.... Makes me wonder why I still have a 928 as the Mercedes now makes my car feel like I'm back in a 944.

James Bailey

The automatic has a torque convertor which in effect creates a LOWER first gear by allowing the engine to rev higher quicker which is one reason why so many dedicated drag race cars are automatics.

SwayBar

For a street car, sure, I am confident of that.

However, your comments in the past reveal that you have no idea what's required for a track car and where it operates RPM-wise. And to top it off, you say that you were a crew chief with your misguided ideas, and these were just basic concepts you are completely unaware of. I guess then that the lesson-learned is anyone can be crew chief...

Mongo

Higher stall speed helps too. Although I want to know how to do that mod for my car. IIRC you have to do something with the valve body and not the torque converter.

GregBBRD

No big surprise, this has gotten really, really stupid.

I've never said I'm trying to make more torque at 2500 rpms.....who would care about that? However, If I've got a street engine that will cruise down the freeway in 5th gear at 2500 rpms and still be able to accelerate (automatic or 5 speed) with partial throttle smoothly, I'm happy with that! Who wouldn't be? I fully expect that if someone desires to go to full throttle at that speed, they will grab two gears and rocket forward. Van's engine does this EXCEPTIONALLY well!

I'm also saying the same thing I've always said....never, never sacrifice midrange torque for high rpm horsepower. Never, never be fooled into that trade! It's far better (and cheaper) to have an engine that has its best performance from 4,000 to 6,000 rpms, than the exact same engine engine with a bigger cam (or intake) that has its best performance from 5500 to 7,500 rpms. The engine wil last longer, be less likely to puke oil out the breathers, be less likely to uncover the pick-up.....the list goes on and on.

I've been driving two GT's and a GTS around for a couple of weeks, looking for some intermittent issues. While I have certainly had all of these cars near redline to test, I bet I haven't been over 4,000 rpms 99% of the time.

I just don't drive the cars like that.....unless I'm racing.

And talking to my clients, the vast majority don't run their cars to 6500 very often.....and spend most of their time cruising around.

So, building a dedicated manifold that ONLY improves horsepower from 5,500 rpms to 7,000 rpms makes no sense, for me...or my hundreds of clients. I'll be looking for improvements from 3500 to 6,000....and if there are significant gains below and above that point (which there will be with my new intake....we've already shown this), that will just be the icing on the cake.

BauerR

No pix yet but my plan is for everything to work under the stock hood and to run a 90mm TB. Also working with the stock MAF and airbox locations.
I'm building this for me and my car and what I want out of MY car. It will be available to the public also when finished, should anyone be interested.

Imo000

Stall speed is done by the torque converter. Yo would need to remove it and replace it with one that was internally built for a higher stall speed.

ptuomov

Pretty much no intake manifold that runs well up to 6500 rpm is going to beat the stock S4 intake manifold in the flappy closed mode at 3000 rpm in terms of torque. That's just the way it is. A new bolt-on intake manifold starts making sense if you have more than enough torque at 3000rpm and want to trade off some of that to more power and torque in the 3500-6500 rpm range. Above 6500 rpm its likely a whole custom motor project anyway.

mark kibort

yes, this is a valid point and is true

yes, for someone like greg to continue to make comments about his "midrange" torque, and "unwilling to sacrafice" it, as well as his belief of "torque winning races and HP selling cars" mind set, its like he has never done two things...... A- taken a physics class, and B- read a racing text book powertrain chapter. this is very simple stuff, and i think ive made it quite simple by giving HP as the " torque at the rear wheels at any vehicle speed" equivilance . it cant be proven wrong, so i dont know why anyone doubts it to be true. If anyone can, ill buy them $100 of gear at 928intl

interesting!

This is exactly what we are talking about here. there is no NEED for flappy being closed if you are on a race track or ever want max acceleration potential even on the street. its a "feelly" thing, that allows you to have a little more HP (about 30 or so) when you dont want to downshift. ......... you down shift, and you gain near 50 HP. so, if you want a 50% greater acceleration than flappy closed, just downshift.
this is exactly the reason i pulled flappy out of intake. too risky if it failed as it would kill 4500rpm HP and below 3500rpm was NEVER used at the track WOT.