high impact

iTrader: (5)

I am in the process of installing a cam, springs, pushrods, smooth bellow, intake and throttle body on my bolt on M6 formula. My original plans were to install a ported 90 with a 92 Big Mouth TB along with my TSP231/237 cam and reuse my stock 241 heads with new valve seals. I plan on spraying 100-150 shot later. I have been slowly acquiring parts over the past few months and have all these currently in my possession.

I now have an option to run a 102 Fast intake OR my ported 90. I do have fuel rails but they are for ls1/ls6 style, I can fabricate some brackets but I do not have larger than stock injectors. I can't imagine I would notice any difference between the stock 102 and the ported 90...or would I? I know that I would be better prepared for larger heads down the road if I used the 102 now.

My questions are, IS this a good move to use the 102 with the 92 TB and stock heads or should I wait to step up to the 102 when I get better flowing heads? Will i see any gains or will this just be additional work and unnecessary at this time?

high impact

iTrader: (5)

Nobody has any insight on this?

I've done some research on this and still not 100% sure if I can/should run the 92 TB with the 102 intake. I understand it will bolt up.

Darkman

iTrader: (2)

You are right at the border line. A ported FAST 90 will support flows up to 280 cfm, which is just adequate for your current heads. As soon as you improve your heads the 90 will be a restriction whereas the 102 intake would not.


https://ls1tech.com/forums/7248108-post1.html

wildcamaro

iTrader: (15)

If I were you I would run the fast 90 until you get a 102 throttle body bc what's the sense of choking a fast 102 with a 10mm smaller throttle body...common sense would suggest the 92/90 combo would produce a more laminar airflow than a sudden jump from the 92 to 102...don't get me wrong there are prob people out there Doing it but just because it runs doesn't mean it's running at optimum efficiency..

Darkman

iTrader: (2)

That is not quite the way it works. You can have a build that requires all (or even more than all) of the capacity of the FAST 102 intake, and yet not require any more than a 90 mm or 92 mm throttle body. On such a bulid, installing a 102 mm throttle body will do no harm (setting aside tune difficulty) but will not add horsepower.

wildcamaro

iTrader: (15)

I'm discussing from a fluid dynamic stand point of creating therapy turbulence possible, you can't tell me an abrupt 10mm change between throttle and intake has no effect on the turbulence...whether its negligible or not I'm not sure, I would just prefer to keep my diameters as close the same if at all possible...like the other guy said you have to take in to account the cam the heads flow so unless dunk testing is done we are pretty much all just stating opinions here...I'm just trying to say that bigger isn't always better, people always look at volume and not velocity/shape...so you may be right, maybe not

wildcamaro

iTrader: (15)

Least* not therapy lol

high impact

iTrader: (5)

I may be picking up a pair of ported 5.3 heads now and bumping my compression. I am pretty convinced the 102 with the 92 TB is the best option. I was concerned about the 10 millimeter shelf transition as well but will compare when the 102 shows up. I wonder if the square edge can be ported smoother OR does it REALLY create an issue since the air flow moves into a larger diameter - not the other way around...

wildcamaro

iTrader: (15)

The 102 gives you room to grow that's the nice thing about it...whenever you get the cash in the future you can go with the bigger lid/maf/tb etc...my engineering background gets me thinking about the little **** lol, anyway good luck bro

Darkman

iTrader: (2)

Here is one discussion of the turbulence issue, and mention of an adaptor to address it.

https://ls1tech.com/forums/generatio...02-intake.html

I run a FAST 102 intake with a stock LS2 90mm throttlebody. It was tuned by PatrickG and I have no drivability issues.

wildcamaro

iTrader: (15)

The turbulence I was talking about would probably be impossible to feel, I would bet though if the 92/102 was compared to the 102/102 combo there would be gains and not just from the bigger cross sectional area of the 102, it would be a combined effect of volume and laminar flow...I was just always taught that direction change, abrupt diameter change, and cross sectional area change will effect flow...like I said it may be negligible but it's there

wildcamaro

iTrader: (15)

Just looked at the above thread, that has some good info about the point I was trying to make...

Darkman

iTrader: (2)

The turbulence theory suffers from some factual infirmities that are not clear. First of all, if you look at the inside diameter of any throttle body you will see that the opening is always smaller that the hole going into the intake i.e. a 78mm throttle body has an internal diameter much less than 78mm, and the 90mm throttle body has an internal diameter much less than 90mm. And so on - so there is always a mismatch to some extent.

Secondly, it is not clear that turbulence at the mouth of the intake will translate into turbulence through the internal intake central chamber, which acts like a central storage vessel, and then survive as turbulence to be transferred into the individual runners.

In summary, any turbulence at the mouth of the intake should not be assumed to be as disruptive as, for example, as turbulence at the end of the runner into the cylinder head from a mismatched intake/port.

wildcamaro

iTrader: (15)

Which could be true, I haven't exactly gathered experimental data I'm just using basic fluid theories...like I said its probably negligible but I wanted to mention...maybe you have more experience with the said topic...I'm not trying to say you're wrong and I'm right sort of thing...just having an Internet discussion that's all

bww3588

iTrader: (49)

You would have to be right on the edge of maxing out the intake before you felt any loss/gain from turbulence in the mouth. The plenum has enough reserve of air to act as a cushion to eat up any turbulence. Like said above, you would have to deplete the reserve of air (putting the intake under vacuum) before any turbulence would be transmitted to the cylinders.

Now, if you put a 102 tb on a stock ls1 intake with a 408 to feed...you'd probably feel the loss from the turbulence...if you could isolate and feel that loss independent of any other negatives.