I'm not worried about the intake. Just the effects of the ledge.
The fine droplets of fuel spray accumulate and then drip off the ledge? The drops are too large to atomize and this makes for finicky tuning?

 

the tip of the injector will sit right at that ledge, spraying fuel below the ledge your worried about. nothing will puddle up or drip off of it.

if your that worried about it, you can have the intake surface of the heads milled some to bring the intake manifold down in better alignment, BUT, then you risk throwing the port alignment off, causing TB interference with pulleys...etc. not worth the risk IMO.

I agree, run it, esp with the given examples and testimonials from reputable people on here such as TSP and SweetS10V8.

 

With the design of the intake it's not going to be sitting at the ledge. The injector is quite a bit higher.

 

So are you going to worry/talk about it forever, or are you going to give it a try? Ive given you answers. What is the answer that you want someone to tell you that will make it "all better"?

You can talk till your blue in the face, and worry till you get ulsers. But your not going to KNOW anything until you actually do something. Thats the downfall of our world of too much information, it can be a hinderance to progress.......

If it doesnt work, an intake manifold swap is as simple as it gets......but there are litterally 1000s and 1000s of these intakes out there, and you think your going to be the only one with an issue that you are seeing happening in your mind? Your overthinking

 

Wow! Well I've already done something. I'm returning it and finding something different. If it was a bolt on truck with cam, headers, intake etc I'd run it. I have too much invested to do it half ***. Several say it's fine but two guys that have built a ton of engines say it's not..... It may be like this on several vehicles but sorry I won't run it on mine. I'm just talking about it because I'm replying to others people's posts.

 

I've never heard someone call FAST intake half *** before

 

Sorry I guess. My first one....Maybe it's just mine.

 

Sorry Im late to the party....

The problem is that FAST changed the position of the injector nozzle on the new 102 style redesign....

ALL the 102 style manifolds will position the injector higher in the head which does give it a better vantage point on the back of the intake valve it is being aimed at.

Luckily, I was in the middle of the AFR "V2" LS head redesign when this manifold was released and I made changes to all the AFR cathedral heads to accommodate what I felt at the time was a slightly better position of the injector (arguably), but either way a design change to the injector location that needed to be addressed in an effort to eliminate a step (or a shrouded hole) like the picture you provided clearly shows. I was concerned not addressing it might cause atomized fuel hitting a lip to fall out of suspension (possibly creating larger drops and some puddling instead of a fine mist).

The FAST 102 has been out for quite awhile and I suspect some heads and some injector types could be effected worse than others but the logical choice for me at the time was to modify all the port inlet shapes of the new AFR line and eliminate it from the equation.

Will the motor run that way?....of course. Is it ideal?...personally I don't think so and if were my own engine I would address it which is easy with some basic grinding skills. You just need to bolt the intake down and use a scribe in the holes to mark the part of the head that has to be addressed. Then using a grinder and a bit meant for cutting aluminum, raise the cathedral section of the port and blend that raised section into whats currently there (basically elongating the cathedral section of the port).

Like so....this was the engine I was building at the time that I realized we had an issue with the FAST 102 new injector location so I massaged the injector roof of these heads by hand because I wanted to get this motor finished and wasn't about to wait on a new CNC program to be written.



The answer isn't to ditch the FAST.....the answer is to rework the heads a little to better accommodate a far superior manifold than any other you can possibly bolt on.

Hot rodding.....building engines.....its not always a walk in the park and obstacles like this occasionally sneak into the picture. Luckily this particular situation is easily rectified if you have decent hands and even basic grinding skills. If not pay someone that does but its not a megabuck kind of deal either way.

Hope this helps.....and just to clarify, every new AFR V2 head we sell (our entire product line) is already shaped for perfect injector clearance with the new line of 102mm FAST intakes. Its a non event with an AFR headed combo.

Also, considering the fact there are 100's of combinations out in the field like this you have to resort to some basic logic and accept the fact it obviously still works, but if your like me and prefer to optimize every where you can, I think its a worthwhile investment of you time if your particular head leaves a step large enough to warrant the "fix" or improvement. Either way, addressed or not, you should run the FAST, your engine will produce the best results if you do....and better yet run a ported FAST for even stronger results, significantly stronger trying to push close to two atmospheres thru it!

(Shameless plug for Mamofied FAST!! )

-Tony

PS....OP....Im going to dyno a brand new ported LSXR-T in about three weeks....Im selling it directly after because it wont fit in my Vette (not without a foot tall hood scoop at least!) Anyway, PM me if you have an interest in that unit....I will discount it slightly and it will be brand new with about three dyno pulls on it....ported and ready to rock and roll on your combo!

 

Thank you Tony! Finally someone who knows exactly what is going on. Even FAST couldn't even tell me they redesigned the injector location!

 

You've given the answers your limited education and understanding allows you to give.

The man had/has reasonable concerns and those concerns where not being addressed by your so called answers.

Luckily for the OP and you, there are already people who know. Those that have been there and done that. Some with engineering degree's and such, perhaps even make a living out of this kind of thing. The OP's downfall in this thread is the lack of information, not too much of it.

There are literally tens of thousands of performance vehicles (name your poison) that aren't working anywhere near their potential. Mainly because of the horrible advice they get from uneducated "professional wannabe's" on "tech" forums. The OP was far from overthinking, he merely had a thought. Maybe you should get one?

 

I didn't know fast redesigned the injector boss...now I see the concern. However, as tony explained, a few hours with a grinder can solve it.

Even if it was not fixed and ran as is, I see the outcome still being better than alternative manifolds for cathedral port heads, unless some serious cash is dropped on a sheet metal intake.

I'm curious as to what route the op took as far as an intake. Esp how much is supposedly invested.

 

I have a feeling unless a sheet metal intake was chosen, power will be left on The table, even with the injector boss problem not addressed. It is tough to beat the bread box intake that is the lsx-rt.

 

I've still have the FAST intake. Actually having the business that I purchased the engine and intake from check on the Holley Modular Hi Ram which is now available for cathedral port heads. For how much I have invested.....It's probably no where near what some guys have spent but way more then most. I'd hate to add it all up right now.

 

With a forced induction application I don't know how much difference it will really make? You don't need the best flowing intake and cylinder heads when you're forcing the air in there. Lots of guys running the stock truck intake have made really big numbers.

 

I forgot you were going fi.

Both intakes are great options, but what's to say the holley intake won't have the same problem?

 

Probably true but I'm hoping not.

 

INTERNET (FAIL) MYTH 102

"Im building a forced induction engine.....I dont need a good intake because the air is being forced in"

How many times have you guys read that or something similar??

Lets talk about that for a minute.....

Bottom line, I would say most would be in general agreement saying the addition of a much better flowing intake manifold (say a ported FAST hypothetically) will make a good deal more power in a normally aspirated application (especially) assuming a good head is being used. Whats the norm....20-30 HP depending on the rest of the combo.....I would say that's fairly accurate.

Why does the engine pick up? The better shaped manifold allows more air to enter the "combustion process"....when mixed with the right amount of additional fuel more power is yielded from a larger explosion (higher cylinder pressure).

Everyone thinks a normally aspriratd engine "sucks" while a forced induction engines intake tract is pressure fed and there in lies the problem thinking.

A normally aspirated engine is under pressure also.....its just under (typically) 1 atmosphere or 1 Barr of pressure (14.5 PSI). A boosted engine simply references how much additional PSI of pressure is added to the mix (a forced induction application thats showing 10 lbs of boost is experiencing atmospheric pressure plus an additional 10 PSI), but make no mistake about the fact that both intake ports......the normally aspirated engine and the boosted engine are both under pressure and when you increase the flow potential and efficiency of the manifold your going to make more power in either configuration...in fact a blower engine makes more power per cube and increasing its breathing ability more has the potential to show you even greater gains with a better set of heads or a better flowing manifold.....the gains are essentially compounded by the additional pressure on the back of the intake valve.

People's perception of boosted combo's are also skewed because even a "so-so" forced induction combination is still capable of laying down a somewhat impressive number (as it relates to a normally aspirated version of the same)....most people not realizing the better heads, better manifolds, etc. could help to increase that output significantly.

I recently helped a customer with a Mamofied set of AFR 245's......his baseline was a stout combo....basically a 402 CID engine making low 800's RWHP with set of 225's I massaged for him some years back. Now with less static compression in the new combination (about a half a point less) he picked up 75 ft/lbs and 75 HP to the rear wheel. No way would he have seen anything like those gains N/A and I bet had he taken a poll most people would have said the heads don't matter that much with a boosted combo...."your forcing the the air into the engine".

Hope this gives you guys some food for thought and a different perspective on boosted versus normally aspirated combinations. If you install a better intake on a boosted combo and don't see good gains, that simply means you have other restrictions in the pipeline (a weak exhaust port in the head, the wrong cam profile, a restrictive exhaust, etc. etc.).

Sorry for the semi rant.....I'm going to have to remember to go back to this thread and copy and paste this post in other threads that discount airflow and efficiency related improvements in boosted combos.



Regards,
Tony

 

Engine thoery 101; Day 1, minute one, "Hello class, lets start......."An engine is an air pump, the more efficiantly it can intake and exhaust air the more power it will make." (not a shot at OP, I just have heard the "i dont need to worry about the intake side becasue Im forcing air in" even while in college)

Ive heard it a ton of times from end-users and I always simplfy that statement to a few simple things when trying to explain it to people;

1. Boost is a measurement of restriction, not airflow!
2. With better heads, youll make more power on less boost. Then you have the option to turn the boost back to where it was.

But what would I know, Im just some uneducated, wannabe professional, who has never worked a day in the automotive aftermarket. And surely hasent EVER worked on the FAST manifolds......

 

Tony, Good info as usual. To the OP good catch. Its the little things like your find that has some combos running better then others with the same parts. After all a bolt on part doesn't exsist in the world of cars.

 

plus more restriction makes more heat. i put a hand ported supercharger and intake manifold on my car and was able to pull another 20hp and 42lbs of torque out of it on the dyno. take it from someone boosted. it ALL matters.