Old Geezer

iTrader: (3)

We just completed back to back tests of 3 different stock rails, same set of injs, same PCM, same pump,,,Found NO difference in flow between 1 and 7.[Or any other inj, for that matter.] Might be a different case if the injs are dirty w/ the crap Jimmy is mentioning.. A clean system worked perfectly.
The test bench:
ASNU inj bench, stabilized power sources, modded G-van PCM, LS1 injectors that I had previously cleaned and flowed.

More to come...

HASTINGSRJ

iTrader: (18)

Maybe its something that can be compensated within the tune

DiabloFormula

iTrader: (58)

I still have my LS1 coolant tubes, when I went ot a LS6 intake I just hammered down on them to slightly oval the tube, it's worked great for both my LS6 and my FAST intake swaps.

SOMbitch

iTrader: (8)

If you have your injectors cleaned and flow tested run the richest ones on 7/8.

silverM6TA

iTrader: (5)

so what exactly are you guys saying? if i did a FAST 90 swap i COULDNT use my stock cooling tubes or what? i dont understand...

01camarosspower

I have seen 2 engines in the past month with this problem. Both running fast 92 with fast throttle bodies and trick flow heads. One forged bottom end and the other stock. Built and tuned at different shops, but both have the same problem. Also both engines broke exhaust rocker arm on cylinder 7 and were not over reved. I am leaning toward a flaw in the fast intake. maybe it sends too much air to cylinder 7 and makes it run lean? No doubt that the FAST intake makes power, but I would much rather have reliability than a extra 10-15 hp.

ryan@rpm

iTrader: (5)

I have seen two do this myself on the same cylinder. I have been running the **** out of mine with a 90/90, H/C setup on a 98 stock bottom(96K) with dang near 12:1 on pump gas with no failure ?? But mine is ported so that could make a diff. in the air flow to #7 ? I do have my coolant blocked off in the back as well. I like hearing everyone's opinion on this as well . It has me thinking if it is a cooling problem, mine has a 160 thermo in it and will not break 185 degree's on the hottest day in the summer ... Is this possibly why mine has lived so long ?

Zaxz28

I am wondering do the ls6's have the same problem? Do they have the same cooling passages as the ls1?

fortmyerspolice

iTrader: (7)

So the solution to the #7 8 getting hot is to add another cooling tube in the back with one already in the front?

BlackScreaminMachine

iTrader: (17)

Exactly, I did not read the rest of the posts as this is the correct one, its a heat issue, not a air issue.

Brakemotive

iTrader: (73)

This issue is address in Will Hanzel's How to Build LS1/6 engines book. And yes he claims it is due to the cooling crossover being removed. You can modify the underside of an LS6 intake and push down the tubes to work, but those with a FAST intake have almost ZERO room to fit an LS1 style crossover tube.

Like SOMbitch said, if you have flow matched injectors you can compensate by putting the highest flowing ones in the rear cylinders.

Anyone have any bright ideas for how to run a crossover tube from the front to the rear on a FAST intake? Anyone done this, pics?

DiabloFormula

iTrader: (58)

No pics, but when I switched from my LS6 intake to the FAST 90/90 i did nothing to my tubes, previously with the LS6 intake I ovaled them down and took all the mesh and clips off, haven't had any problems yet.

And I'm spraying on top of that, so I figure if this was an issue...my motor would have been toast awhile ago.