I would like to know which is a better intake for a TPI C4?

 

If it is pretty much only a street car -for the $ it takes to get through it.....neither.....just bolton some type of power enhancer onto your current TPI application and let her rip.

 

the first TPI is pretty rockin... the TPIS is a modified copy... I still prefer the HSR
but you will have rails, regulator and hooking up fuel lines and vacuum on any aftermarket
and if you install these system on you will need a cam to match the new RPM range and a TUNE

PS if your state requires emissions a EGR setup is required

 

Which would make the Superram the better choice. OTOH, the FIRST does have provisions for EGR but the hook-up would need to be fabricated.

FWIW, I wouldn't be afraid to try AFR195s with a factory cam and a FIRST. The heads would provide extra breathing with superior mid-lift numbers and the cam would still be reasonably close to the larger TPI setup. Tubes close enough to the same length.

A FIRST or SR by themselves aren't something to snub (w/o cam/heads) if the right price came along.

But the SR has to get the edge if fabrication is an issue.


As far as powerbands, they have to be pretty darn close. FIRST might have a bit more down low and visa-versa.

 

For the street, I'd just keep the stock TPI set up. Just add an under drive pulley set and K&N Filter and clean or new TB. Also, if you haven't already start with the exhaust.

 

stock is fine, you save money, if your Vette is an addictive hobby, god help you.

 

do the first. call Kevin he is a really good guy that would not steer you wrong. first manifold is no slouch.

 

Just for general information a First intake system will out flow a Super Ram by 40 to 50 cfm when both are "out of the box".

 

89TA whats your opnion of a worked over SR and FIRST as far as behavior/powerband?

 

I'd like to see someone port a FIRST. Thing would flow some serious air. I have no idea about "3rd wave tuning" or any of that other stuff i've read about on TGO. Confusees the hell out of me.

 

Its the same thing as tech correct " Finate Amlpitude Waves".

Tuned for an optimal RPM operating powerband.

Brian

 

You should read about intake reversion. It's not rocket science. Since cam lobes are oval, they can't open/close like a light switch. That process is more gradual. Because of that, valves are left open BEYOND when a cylinder reaches the bottom of it's intake stroke. As it goes back up, the valve finally closes. But, not before air "reverts" back up into the intake.

The how, when, where's of that reversion creates an extra pressurization against incoming air. It's called wave tuning. Engines operate in pulses -- which create pressure waves. Tuning for those waves (with runner length, cam events, and/or exhaust shape) will directly affect peak power production.

Also google, David Vizzard's "Exhaust Science". Great article which explains exhaust tuning. Knowing about both intake/exhaust tuning can help create a better build.

I would too. I know of two people who started down that road. As with others affected by this economy, they've gotten delayed. But, they're out there and will post about it one day.

I can't wait to read about it!

 

It has never been explained to me like that. Thanks!

As usual, someone comes through with an answer.

I'd like to read about it too. Imagine the torque.

 

That is almost 100 % correct Greg.

But it also works in a total vacuum too.

"Particle Movement" is a better method of understanding.

BR

 

First I've heard of an engine working w/o air.

 

Yes,

LOL.

It won't run without Oxygen in the air.

I have brought this up before,

Too hard to explain easily on C4.

I know that a few have read on their own in the past on "Finate Amlpitude waves.

You have used them to your benefit in your 383 build in your 1989 C4 Coupe too,

Possibly without knowing so Greg.

Those invisible waves inside of a running 4- stroke engine are 10,000 times more powerful than it takes in audible sound wave pressures to blow a human ear drum out.

Done right,

It draws more air in or more importantly Oxygen to mix with gasoline or alcohol fuel.

End result is more Torque, HP. & wider operating RPM powerband.

I had a good teacher Greg on engines & all aspects of auto & truck repair.

1 on 1 for 20 some years.

Brian

 

Didn't stop me from taking a stab at intake reversion (in 100 words or less.)

Sometimes, you ramble and avoid answers. This is one of those times.

 

Most would disagree and point out I should have used a shorter-runnered intake. But, they didn't understand my goals.

There wasn't much I did in my 383 build without understanding the consequence/result.

 

"89TA whats your opnion of a worked over SR and FIRST as far as behavior/powerband? "

Hi Ron

As far as power band and the rpm range we generally use the Super Ram is geared towards the 3rd harmonic wave. The First with the longer runners is geared towards the 2nd harmonic wave.

IMHO the behavior will depend on the build of the motor such as cam choice, cubic inches, compression etc.

As you know I am currently working on a long tube runner design using the Accel Super Ram base extensively modified. I had Dr J do a preliminary flow on the base only and when he was done with his part of the work. With a small radius on the inlet it flowed 335cfm. With a larger radius on the inlet it flowed 345 cfm.

I had planned on going over to Joe Shermans today and flow the base, runners and plenum attached. However Joe was doing a dyno test and I will have re-schedule an appointment. Another thought is to get with Tony Mamo and flow the whole thing attached to an AFR 195 Competition head.

Back to the First. The base has a lot of material and can be ported quite extensively and up to a Felpro 1207 intake gasket. IMHO the restriction would be the runners once you go so big. How do you get in there and open them up all the way? I think you could go to a 1.90" diameter on the runners if one could get in there all the way. The inlet on the base will go to 2" easy enough.

On the Super Ram we have gone out to 1.8" on the runners but that includes welding and spacers in order to use longer bolts.