Could anything before the runner intake possibly be too big or it shouldn't have any affect on head velocity? Just harder to tune the bigger you go? Trying to figure out how some people are getting the same/worse numbers by swapping the fast 92 to a 102.

Does anybody know how much bigger the runners are on the 102mm vs the 90-92mm?

 

most people show no lose of power ,the fast website shows a 5hp increase.talk to Tony Mamo or Ron at vengeance racing about runner size.

 

There is good thread Ron did over in external if you search. I will say if I didn't already have the FAST 90 I would have gotten a 102 for this latest combo. I don't think it is worth the $$ to ditch a 90 just to step up to a 102 though. I just opted to get my 90 ported....

 

I would like to believe that the 102 would be great for our cars ,but I really haven't seen anyone post anything "positive" about a 102 set-up on a stock 346 bottom end engine with heads and cam yet. I want to see track numbers with the 102 and I don't care about dyno numbers at all.

Now on larger cube motors ,I can see it working very well. Is 5hp worth the price of a 102 intake ?????

Personally, I would rather have a 92/92 set-up and call it a day with my current set-up. Now if I had a 370 or larger motor ,I would get a 102 in a heartbeat.

 

Yea, I was really thinking a used 92/92 set-up would be better on a 346 since it uses the stock fuel rails and should be plenty of air once ported. Similar to a 102mm. the 92mm throttle body should be easier to tune than the giant 102mm tb also. Like you said though on a bigger motor like a ls3/408/440, there should be a good gain in using the 102mm manifold.

 

i like my 92/92 set up alot... it seems to work out quite well for my car... and i also havent heard much positive feed back on the 102... So ill stick to what i know works

 

8,000,000 threads on the subject....you're bound to find what you're looking for.

 

I have a FAST102 LSXr and a NW 102TB. The big blade makes no difference in driveability. There are some gains over the 90 set up. Not big gains. Maybe about 6 ftlbs in the middle of the curve. If you need to buy a new TB anyway consider the 102 on a stock 346. The 90 is pretty close though. If I had a bigger cam I think the 102 would put up some even bigger numbers. See this thread.

https://ls1tech.com/forums/cadillac-...02-tb-ls6.html

There is a dyno sheet comparing the 90 to the 102 TB.

 

Very interesting BigBUBU, I tried to do some math to better understand the power increase.

At 6500rpm the engine needs 641 cfm assuming 98% volumetric efficiency which H/C cars should have around.

6500rpm / 2 x 5.7L x 0.98VE = 18,155 Liters per minute or 641 cfm.
.

 

Using a calculator I have found online: 98%VE, 80 degrees, 102mm tb x 2in, 5.7L, 6500rpm, it shows a total cfm of 641cfm just as calculated above. Also says there is only a 3.3hp power loss with a 0.6 kPA drop

The 92mm throttle body gives a 5.1hp loss with a 0.9 kPA drop.

The stock throttle body gives a 11hp loss and 1.97 kPA loss

(Formula assumes 463hp, and no throttle blade air flow interference)

 

We have done extensive testing on the LSXR 102mm manifold and found that the gains on a stock cubic inch combo are similar to those of the previous 92mm version. The 102 does shine thru the midrange and peak ever so slightly over the 92mm..... The key to not losing bottom end is to not run too large of a TB on smaller cubic inch combinations. Most of our heads/cam combos run a Nick Williams 96mm throttlebody.

Do a quick search and you will see quite a few results of the new 102 on various combinations we have tested it on...

If anyone has any other questions about their specific combo feel free to give us a call.

 

I've done a search on the 102 Intake and mostly everything I found was an LS2 and larger cubic inch motor using them and I would too if I had 370 or more cubic inch block . I did found one guy that installed the 102/102 on his LS1 ,but the thread didn't continue/no more updated info.

I just want to see what a FAST 102/96 mm TB will do on a LS1 with H/C set-up on the track and you really can't find one good thread.

Do you guys at Vengence still carry the FAST 96/96 set-ups ? If so ,I would really be interested in that set-up.

https://ls1tech.com/forums/new-produ...-tb-combo.html

 

I cant understand FAST's desire to keep putting out bigger and bigger intakes and seemingly abandon the previous version that worked so well. I hear you even have to shim the subframe on C5 vettes due to the manifold hitting the cowl. Thats the most insane thing I have ever heard.

I think the 90mm was perfect for LS1's

 

Well, you have to step back and look at the order of events when this manifold was released...

When the LSXR manifold (102mm) first came out, it was only for LS7 and L92/LS3 intake ports - all of those engines have larger cubic inch displacements than the LS1, so the larger size made sense. They also featured a modular intake runner - that meant that you could completely remove the intake runners for porting, and you could also retain the upper/lower shells of the intake, yet still make it fit different heads by just swapping to the appropriate port design.

They took this modular concept and had cathedral port intake runners made to fit inside of this manifold for the older LS1/2 crowd - this let them get rid of the old 92 assembly that could only be used on cathedral port heads. This makes perfect sense from a manufacturing standpoint - you end up with one intake manifold design that can be used on 3 different intake ports with only having to swap the runners. You reduce tooling/mold costs while having a more versatile product that can be used on nearly every LS-series engine, new and old.

It clearly wasn't designed to be used on older vettes and f-bodies - the thing is massive compared to a stock intake. That's just an unfortunate side effect of coming up with one product that's supposed to do it all. Blame the free market economy if you must, but they didn't make this decision blindly.

 

Im considering buying a 102 setup but im worried about it being overkill on my stock cube ls1. Ls6 intake is on there now with a cam only but heads are going on over winter.

 

Without a high flowing set of heads you simply wont tap into the full potential of the swap.

And I would agree as LPE403 pointed out that there are likely 8,000,000 posts on this subject (I'm probably a reasonable percentage of that total....LOL)

Guys....you have to have a combo that will tap out the OEM intake to see the big gains. That means for the most part a really good set of heads....the better the heads the larger the gains from the manifold swap.

A 102 FAST intake on a 346 that could use it (an efficient package with good heads and the rest of the typical bolt-on's) will NOT detract from the bottom of the power curve. We are not atomizing fuel here folks (you guys gotta lose the old carb mentality) and the entrance of the intake manifold plenum will not effect the power curve at all in the lower RPM's. Its simply an air blade (a carb can be too big because air speed thru the carb body directly effects the signal and atomization of the fuel), and lets not forget the runner length, size, and shape has not changed a bit. Think of it this way....a 90mm throttle open 20% will make the same power as a 102mm blade opened 16% because they are both moving the same amount of air at that throttle position respectively. The engine doesnt know how much the blade is open....only how much air is available to process and mix with atomized fuel from the injectors.

I personally really like the new 102....it has a far better design (much more rugged), and has a slightly better vantage point to the back of the valve due to the increased height of the runners. Ported properly the exits are more direct than the 90/92 version and it makes a killer intake for most of the hot street/strip cars we are discussing here.

Is it worth a bunch over a properly prepped 90 or 92 mm FAST?....on a small motor not really, but you would see a little more peak. But on a larger motor, especially a larger motor with a honking set of heads and a big appetite for air it would shine even more....especially if it's properly ported. These are not optimized pieces out of the box....due to typical plastic manufacturing issues (compounded by the complexity and multiple pieces that make up the intake) they leave a little to be desired in OEM form. Correcting these issues with a carbide porting tool in addition to some other tricks can reap even larger gains in airflow from the swap. Its all about allowing the cylinder head's intake port to breathe as well as they possibly can. An OEM intake simply cant keep up with a much higher flowing aftermarket head....you can see a 50-60 CFM reduction in airflow with say an LS6 intake versus testing the same intake port with a radius plate in front of it (that represents best case scenario for airflow). Wanna know how well your intake is working....bolt it in front of a cylinder head and see how much it hurts your flow....that's how you evaluate how well the manifold is working...or at least one of the larger parameters of manifold design that effects power production.







The key to this discussion however revolves around the fact it wont hurt the bottom of the curve on a stock displacement engine assuming that engine is a prime swap for this mod to be considered....and that means an engine that's already got good heads, cam, exhaust etc.

Hope this helps....

Now there are 8,000,001 posts on the subject!

-Tony

 

Good post Tony

 

at least THIS one is worth saving! Nice post, Tony!

 

sticky that ^^^^^^^^^ please.

 

Tony, do you know how much bigger the runners are on the 102mm as compared to the 90/92mm or if they are the same size? Thanks