I know that the standard laws of "longer intake runners=more torque" and such must have exceptions when subjected to non-atmospheric conditions (oxygen rich, more pressure, etc). I know my car under nitrous will rev off of my 6000 rpm tach but off of it 5000 is the limit. Will a long tube car respond better to a blower than a mini ram car? Will a superram car do the best because of the huge volume? Any suggestions?

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1991 Firebird
350 L98 (was a 305 TBI),T-5,Edelbrock TES and cat back,Accel manifold
NOS,subframes,jegster torque arm,MSD Digital 6
AFPR,Lakewood lcas
Hurst linelock,SLP cam (206 212 .480 .486),relocated battery,cold air,Hypertech chip,centerforce df,clutch
poly bushings and mounts
AFR 190s
Harland sharp 1.5 rockers
autopower rollbar

12.33 @ 114.83 juiced uncorrected

13.510 @ 102 non juiced uncorrected

 

to be perfectly honest....any intake setup will suffice

i'd either stick with the LTR setup or the miniram depending on the RPM range you want and what kind of motor it is

i wouldn't use the superram because of the possible leaks everywhere, not that it wouldn't work but its just a hassle. Might as well keep the TPI

i know many people who run well with a blower and a TPI

hell there is a STOCK TPI INTAKE car around my neighborhood that has a 383 and a vortech and it goes 10.70s on boost alone

the one main mechanic at ASSC (Larry) has a procharged formula running 10.10 with a D-1 with 15psi and a 100 shot on a 355 with 3.08 gears! He has the TPI intake too but Accel runners

 

No see, you didn't answer my question. What I am saying is that I know manifolds respond differently to boost conditions. I.e. a tpi can rev past 6000 when un-naturally aspirated because air under pressure fills the cylinder faster allowing shorter time and thus more rpm. I just think that the general rules of shorter runner more rpm and vice versa may need some additions when referring to boost conditions. Would a miniram hypothetically have an even higher powerband? Anyone else?

 

I was spinning my 355 TPI motor to 7100 rpm with the s-trim.I do not believe a n/a Tpi motor would ever see that type of rpm.
Just my 02.

 

ok i see what you are saying now.

hypothetically, yes the miniram would have a higher powerband...the reason being is that it is a short runner intake and you DONT have to make up for the long runners WITH BOOST as you do for the LTR setup.

did i answer it now?

The TPI intake works, to just get the rpms out of it you have to make it up with boost, which isn't the best way to do it, but it works.

Where as you could use a miniram intake and with probably half the amount of boost you could get the same powerband out of it with less stress on the motor

 

ttt

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Silly mustang's speed is for F-bodies

 

What does "ttt" mean. Really you didn't answer my question. You are stating all of the things that are commonly discussed yet with no practical explanation for it. I will leave this up to someone with knowledge of intake manifold design

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1991 Firebird
350 L98 (was a 305 TBI),T-5,Edelbrock TES and cat back,Accel manifold
NOS,subframes,jegster torque arm,MSD Digital 6
AFPR,Lakewood lcas
Hurst linelock,SLP cam (206 212 .480 .486),relocated battery,cold air,Hypertech chip,centerforce df,clutch
poly bushings and mounts
AFR 190s
Harland sharp 1.5 rockers
autopower rollbar

12.33 @ 114.83 juiced uncorrected

13.510 @ 102 non juiced uncorrected

 

what, in your opinion, would be the best way, if not with boost? nos?


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1984 Z-28, 305 4bbl, t-tops, K&N. I'm planning a massive modfest involving a new 350 engine w/ TPI. It's gonna be one gangsta of a street demon.

 

I think you try to ask your question differently, but I'll try to answer it. Is cost a factor here, b/c the bolt on blower kits, vortech/ATI are designed for TPI in general. A better flowing engine is going to make more power with less boost readings on a boost gauge and probably a higher RPM. A TPI will still make the lots of power but will require more boost (psi) to do it. More heat/strain in general. If your going to build something where the cost of a new intake manifold doesn't scare you away, go with the miniram/good heads/blower cam. More N/A power=more boosted power. With a blower, the TPI stuff I'd say goes out the window, but then you have these long small runners to force through instead of some nice short fat ones which will be alot easier to force air though. I'm sure a supercharged TPI will look slower to most than a supercharged mini-ram though if you want to suprise people with a high psi TPI engine. What do i know though, i'm only 20 w/ 3 semesters of mechanical engineering and 2 1/2 yrs of wrenching on cars. I Could be all wrong, but someone will point that out soon then.

 

Also 20 with 4 semesters of ME.

How does plenum volume affect power under boost? More boost lag time?? less pressure drop after a cylinder fills?

 

I'd say maybe a larger plenum would create less turbulence in general being a good thing, but i doubt the pressure drops much as most stock centrifugal(spell?)superchargers don't become a limiting factor until 600+ hp is reached. So there's always lots of pressure(air) at higher rpms but no where for it to go due to small/weak flowing heads/cam/exhaust meant to make power N/A.

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14.62@96mph headers, muffler, chip, ghetto stuff, duct tape
89 GTA 305 TPI 5 speed 3.42 gears

 

So what you are saying is that you really don't know. intake turbulence isn't always a bad thing.

 

Im going to try to answer this.The larger runners of the minram for example compared to stock tpi's,cut down on backpressure,and heat in the incomming air,less restriction and a shorter path to the cylinders once entering the manifold.First forget boost,this lb number doesnt mean squat on the gauge anyway,it is totally irellevent,cfm is what matters.you can have a talon making 15lbs and a Camaro running 15lbs of boost,and to say both are taking in the same amount of CFM would be crazy.Boost is a relation to restriction.So yes running a manifold with bigger ports will increase hp over a smaller one as you will reduce intake restriction.The faster you can get the air in and out as unrestricted as possible is what you want.Runnign boost and NOS will make any engine combo run at its maximum VE at all times under the boost or NOS unlike NA which only hits it at certain RPMs.

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Check out my Hompage,or the beginnings of one.355 dynoed at 400HP at 5800RPM & 410LBFT of TQ,on Motorhttp://www.procharged89z.cz28.com/index.html

 

The larger plenum will have to get pressurized before the intake valve sees the pressure, so yes, it'll increase lag *slightly*. The larger volume will help equalize runner flow between all eight, and definitely outweighs the drawback of a little more lag. Besides, the volume of air in the piping, intercooler, etc, is fairly large compared to the intake after the throttlebody (just WAG).

Small clarification - longer, more restrictive runners do *not* heat the incoming air. Having to run higher boost to hit flow numbers with an intake not designed for big flow heats the air.

PS - If anyone in the NorthEast area feels in the mood for some quality track time, a bunch of us crazy f-body folks will be road racing (time trials) at LimeRock on Friday, Nov 2nd with EMRA (http://www.emraracing.org).


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Andris Skulte
Skulte Performance Designs
Z28tt-89 IROC T56 DFI Twin Turbo
http://www.skulte.com