Stage7

iTrader: (1)

Lstvr: any links or more info on the itb Corvette? I like the size of those plenum.

RAMPANT

iTrader: (17)

My Harrop was the opposite, it made a little more power with the complete airbox, y-pipe and filter. Only 5rwhp gain, but it showed a gain. That said the version 1.0 of my motor had issues that are now corrected. When it is on the dyno we will try it again.

My tuner was surprised, as he was sure it would lose something.

They only had a volume of 3.5-4 liters. Not sure why it worked, but it did. Likely works a lot better moving too, as I have the ram air pretty well sealed up feeding both sides. Also curious if the Y connecting both sides help to contribute to the volume. I would bet half of it equals 3-4 liters alone not counting the air lid.

One day I will have a set of CF units that are a lot thinner and should have a little more volume.

O.N.

got any pics of your set up?

RAMPANT

iTrader: (17)

Back on page 4 of this thread.

https://ls1tech.com/forums/13304223-post63.html

A couple more. I modified a set of the original Harrop plenums so that they had 4" oval inlets.

O.N.

That is awesome i cant beleive i missed that, can you post the 2 dyno comparisons if you have them from airbox with/without.

can you post some more specs on the engine/head/cam if possible.
thanks mate.

RAMPANT

iTrader: (17)

More on it here.

https://ls1tech.com/forums/generatio...-my-455-a.html

06vLo

Ok so this may be a dumb question but with this intake setup you have comeing from the same air filter in almost stock form, you think this setup could yeild equivilant numbers if a single throttle body was used in the stock like location where the pipes merge up front? So in sense useing the harrop manifold but your duct work design to a single tb instead of itbs directly on the mani?

lstvr

Its running in a GT Cup race over here in the UK, Its a 5.7 motor as theres no point in it being any bigger thanks to power to weight rules.
The airboxes are one offs, but are bigger than when they first put them on, the main improvement on installing the ITB's was driveability, but we all know that!

Dont know much more im afraid.

RAMPANT

iTrader: (17)

I think a large single would yield similar if not possibly more, where the single falls down is in idle quality and throttle response. The throttle response made the car handle a lot better on the track. There is virtually no lag in accel or deccel. Making it very easy to get maximum grip with your right foot.

My car is for the street so having too much lope will have the local LEO's noticing it. At a 750 rpm idle and no lope, they will hardly give it a second look.

lstvr

I got around +30RWHP from my ITB's, and took my trap from 129 upto 133, if thats any indication?

O.N.

what intake were you running before that?

lstvr

Ported FAST and a NW 90mm TB.

miami993c297

iTrader: (6)

And this is still something holding me on those ITB fitting under the Corvette hood.

Those level of power are easily attainable with a FAST 102/102, and throttle response will be anyway managed by the traction control.

The drivability will be the same or so close with the appropriate camshaft event for the FAST 102.

Air Filtration and Air Intake Temperature will be more under control with a Plastic FAST 102.

Not to mention the cost vs. efficiency...or is there something I don't get?

Christian

3.4camaro

iTrader: (1)

You clearly don't get it. Even a little bit.

Fast 102 won't make the same power, or idle as well. Traction control can't "manage" throttle response. Filtration won't be more "under control" with the fast either. Fast has two good points, cost and bolt-onability.

miami993c297

iTrader: (6)

Hi 3.4camaro,

I am pretty sure you are not speaking of personal experience here...if so would you mind to share it and tell us how much you gained on your car or race car going from ITB to a FAST 90/90 or 92/92 or 102/102 please, I am interested and will share mine obviously.

For now, I am going to stay with my little 418ci, 664 hp na pump gas, revving everyday 7500 rpm, idling 900 rpm without any loop, air filtration report during oil analysis 0 default, and not worried about it since 3 years, and an engine power band pretty elastic.

Before I meet an ITB that will bring me better than that obviously.
Christian

3.4camaro

iTrader: (1)

You aren't speaking from it either. Have you done back to back testing to confirm that throttle response can be "managed" by traction control? any idle rpm deviation studies? any hp/tq difference between your FAST intake and the ITB intake you tested it against? I am a mechanical engineer who did a senior design project on an ITB setup fabricated for an LS1. I graduated based on my research on this specific topic.

Throttle response can't be increased by cutting back on throttle position, which is what traction control does.

Your idle could be 600rpm if you swapped to an itb setup. Separation of air tracts will stop exhaust gas reversion and gas swapping of neighboring cylinders that happens at idle.

You come into this thread and **** on a superior(used in most all racing except drag for some reason) technology because you are having great results without it. I'm happy for you that you have a great running motor, but that doesn't mean you aren't leaving power/driveability on the table.

And I don't know what the last sentence you posted means.

miami993c297

iTrader: (6)

Corner one in Road Atlanta becomes difficult to manage on a high torque engine during the deceleration phase...then it's up to the driver...or the stop watch.

That's the valid point of your development, but I am fine with the engine idling at 900rpm without any "loop"...what is the idling rev of most exotic?

Can you elaborate about the word "****" you are using to define my sentences?

The ITB technology is a very old one, but very old...you must know that as a mechanical engineer who did a senior design project on an ITB setup fabricated for an LS1...if not, go back to the blackboard.

And Yes, ITB is used in most of the racing case, torque management in acceleration phase or deceleration phase is crucial, in most case, those racing engines have a very low torque curve, and a very high power band, isn't it the case?


And try to quote a post entirely if you want to create a real discussion and re-read the sentence in its context, and you will figure the sense of it pretty easily...or don't write to me anymore...your choice
Christian

lstvr

I am speaking with experience, ITB's are far superior in every way except cost...
Mine used to kangaroo and **** about at low RPMs, it is now smoooth!
And makes over 500rwhp from 5600-7000+, before it peaked and died, if you can afford them, then they are the only way to go.

Stage7

iTrader: (1)

I agree, although I will add in complexity in both mechanical setup, tuning, and installing it with proper filtration that will not kill the power benefits of the itb setup.

I do agree with Christian that in certain setups it just doesn't make sense, and there are setups where it won't make any more power. If the FAST is not a restriction on the motor, the itb will likely not make much more power if at all. Plus the itb has to be of proper size and design for the combo.

The one thing it will always do is idle better. That may not be a big deal for most, but I hate living with engines that are overly loud and rowdy under normal driving conditions. I only want it loud under WOT personally, and nothing sounds better than an itb singing under WOT imo.

There are some manifolds that will produce a higher peak #, but not many that will produce as wide a torque curve as an itb intake. It's epic in a big motor and really almost like an electric motor (pulls from idle to 7k rpm). One has to experience it to understand. It is different.

RAMPANT

iTrader: (17)

Even though my motor was wounded, the first time I took it to an autocorss. Yes autocrossing 530rwhp/522rtq. BTW these are thee wounded numbers.

I had instant power application and modulation. My old set up was 412 LS2 with 510/490 at a little higher rpm with a FAST 90. That motor would snap out on me all the time. I constantly had to tiptoe around the corner exits. There was always the slightest little delay in the power coming ion and I had to guess if my foot was in the right location for the power I hoped the tires would hold. 90% I had too little and 10% too much. There really is a delay that I could sense, nothing like a turbo car but enough to screw you up.


With the ITB I feed into the throttle on exit and if it gives a little wiggle I just lift a hair and it hooks right up again. If you have not felt it, you will not know what I am talking about. My car is cable actuated, so the fly by wire guys, I bet it feels more like the single TB.

I was bitching about local rules that said an ITB moved me into the full on race car Paxxing, but a blown 346 was ok as a modified class. Once I drove the car with the ITB, I understood the rules.

BTW, with the 532rwhp, I raced in a heavy rain on 4 x 315 R888s, and was only 3-4 sec behind an AWD STI. In the dry I was 6 sec ahead of him, but it showed me the throttle control the ITBs gave me. It was very slick and I hardly spun a tire. Unreal!

If you ever have a chance to drive a cable version, take it, you will be impressed, I promise.