WKMCD

Encouraging - but a lot of work for a bolt on mod.

Thanks!

Can't wait to see how these perform in the L92/LS3 iteration.

Gannet

First-rate work! Thanks for posting up!

Now, in your spare time, you need to work out a painted (with or without logo removal) option.

Question: do the stock fuel rail covers fit with this setup?

Vette960

Thanks for all your effort in wringing out the new Fast manifold! I'm happy
because I have one sitting on my bench ready to be installed. Before I change things
out I wanted to be sure I had all my ducks lined up - especially the injectors.
In reading your posts it wasn't clear if you used the 60# inj for all your tests.
If you did, then in my situation - minor mods i.e.,LGMs,102 Fast,K&N and tune -
the injectors are the key,period.Cleanup porting is insignificant.
So new injectors won't break the bank, but new rails would be pushing it. Are
these short or long injectors? I'll mod the rails if necessary.
Many thanks again for your work and postings.
Vette960

novaz06

great work carlos!

ringram

What makes you think you needed more injector? What was AFR under WOT with the stock ones and the Fast?

double06

Carlos are you going to test on a Black Mamba cammed car? As you pointed out maybe bigger cube or bigger cammed cars may beneift more in top end?

Vette960

Good question. Carlos had said earlier-I believe it was Carlos? - that the GM injectors were junk.
Better/more reliable injectors removed another variable? I too would like to know what the
AFR was on the best Fast run.

obzidian

I believe it's not a matter of needing more fuel but improving the spray/atomization characteristics you'll get with a better injector. Apparently, the way the fuel is delivered is the KEY factor, according to carlos, to make decent power out of the FAST 102mm and the 60lbs. just do a better job or better put, are more compatible with the fast intake than the stockers. So, its not a matter of we are running out of fuel... its a matter of IMPROVING the way it gets injected.

Now, i believe I called it in the other thread! My guess was right, the cleaned up version is the one to go with! WooHoo.... about a Sweeet deal on a Fast 102mm..... hell, i'll take that beat up test unit for half!


No, honestly, great work and way to hustle! I know even scheduling the dyno time is tricky and ya'll pulled it off. Hats off to ya...


Now... since ya'll are in the testing mods... how about a part 2 to your testing? I feel, that if you shorten the runners a bit, you maybe be able to squeeze a few more ponies at an expense of some trq.

Also, is there a tool where you can INDIVIDUALLY test each cylinder for airflow efficiency or overall efficiency so, in theory, you can fine tune EACH cylinder by adjusting that cylinders specific "air-tube"?

0Myhardtop

Thank you Sir.

And yes, every FAST test mule had the 60 pound injectors on board. The ported LS7 was tested with the factory units.

The cleaning goes a long way, just wait until you see how imperfect it is...it may or may not match flush with your heads; look at it closely and measure.

These are the long versions injectors, the stock fuel rail touches the top of the intake and it does not allow for a full press down.

Thanks,
Carlos

0Myhardtop

What makes you think you needed more injector? What was AFR under WOT with the stock ones and the Fast?


The stock units are rated at about 41 to 42lbs and for some reason, when installed with the FAST, the car simply did not have that get up and go and it felt like it was straining but who knows, your car may be different.

Also, the flow characteristics and ability for better fuel atomization sealed the deal for me. Once we swapped these babies in, the car began to produce some power after more tuning and then more and more after cleaning. What’s even better is how it feels on the road once real volume of air was really getting rammed in there.

ALL runs with each intake we used between 12.4 and 12.5 for consistency and apples to apples comparing.

Personally, I think a tad more fuel under cooler climate with the FAST will generate slightly more power. Remember, cooler denser air with a little more fuel produces the best power. This is why I usually run a fatter A/F in my cars/tune. Yeah, I may leave about 5 to 8 ponies on the table when ambient temps are higher. The fuel is there as the sun goes down and the cooler temps become available. Besides, I like having some extra fuel to also cool off the combustion during these hot summer days.

Some tuners may tune for slightly leaner A/F in the heat and this helps make a little more power in the summer, but I just prefer to give up a few ponies here and there and have the car live happier in the long run. It can be 108* outside, have my AC blasting with two guys in the car and it will not knock one bit while the A/F stays between 12.3 and 12.5 on the road.


Thanks,
Carlos

0Myhardtop

Black Mamba is set for later next week or the early part of the following week. We are playing catch up right now.

Thanks for asking.

Carlos

obzidian

Well, simply put, through the KPa values, you are seeing an increasing in air volume. The stock injectors are tuned to a certain volume and flow figures/characteristic. With this intake, it would seem, the increase in air volume is over-powering the fuel flow from the stock injectors.. thus the need for a better flowing, higher volume injector.

The 42lbs. are fine up to 650rwhp, i believe... so its not a matter of needing more fuel with a maxed of duty cycle......

Is there enough room to potentially shave to top off the fast in certain places inorder to fit the stock rails of is the cross over just not tall enough.

I wonder, since you are already in need of rails... why not just get a set of badass anodized with a an- crossover on the back... would look killer!

0Myhardtop

Brotha,

You go ahead and knock your self out on that, this was enough for me for now.

Now that we have the car/combo optimized, it's time to test our cams with it.

And for those who are not skaaaard, NOS is sweeeet!!

Thanks,
Carlos

Cmarsh

I helped Carlos with this testing/tuning, and the above poster is right...its not the fuel flow itself, but the improved atomization offered by this injector. Infact, that car now make best power @ 12.6-12.8 a/f vs 12.3 with the stock injectors...leading me to believe its getting a better spray pattern into the combustion chamber. The KPA readings is what sealed the deal in my eyes...I knew it was working before I even saw the numbers, and the car just pulls so much harder on the dyno...you can tell its working better.

Chris
Hpp Racing

CNB

Good work guys. Keep us updated on the nitrous results.

0Anthony @ LGMotorsports

You have to ask yourself what would the stock LS7 do with the new injectors? Thats the question that has been posed.

The stock LS7 injectors will support 675rwhp in NA form, so it isnt a supply issue, but a spray pattern/atomization issue.

Good work carlos! Its too bad the pulls were so far apart, you need faster mechanics Tell Cmarsh to get on the stick!!

Louis ( On ants computer )

kenmal5

you guys from Texas rock. Rather than continue the stone throwing that started over this subject, you did something about it. BRAVO ! Not to open a can of worms but trying to understand what the story was with Katech's stock manifold. Was this just a freak? Keep up the good work. PS One of these days will have to pay you guys and Wylie crew a visit. Am in Round Rock, TX. with a stock 427 w/1800mi. Chow, Ken

eldon

Any testing on a sc engine with cam, headers, and meth injection. I already have the 60lb injectors

tjwong

So if the atomization is the issue, then you use the Siemens 46LB injectors which has the same spray pattern as their 60LB injectors. This would give you better turn down and resolution for low speed and idle. A 46LB injector at 4 bar rail pressure is around 53lb and their 63s are at 73LB, just my two bits worth. Maybe Jason can have this same theory tested in their dyno cell, which would be very easy to do for Katech. I would be very interested to see their results using different injectors such as the Siemens which has a cone shaped spray pattern. Are you listening Jason

Cmarsh

We are a busy shop..had alot of cars to tune that day. Thats why we waited till conditions stabilized to exactly the same temp, on the same day. I have done this test twice, on the different days...with the same results.