Great job!!!! How did the putty thing work for keeping crap out of the ring lands. Also, how the heck did you get the piston tops so darn clean, looks awesome!

Did you consider grinding on the head inlet ports to match them to the FAST? I'd love to fill in the FAST with some kind of epoxy, but I'd be too scared that it would come loose sometime in the future and get sucked into the cylinder. I just hate any kind of step that goes into the flow path like that.

 

^^^WOW that is quite a mismatch, seemingly even on top!

Hard to believe Trickflow designs them like this, are those heads designed for a different intake?

Yet there is no doubt those heads are on the fastest LS2's these days so they surely work.

Are you going to do anything about it?

 

Bummer is the mismatch will even be more prominent once the intake is torqued down. I think the Fast is partially to blame as it even is off with the stock heads....wonder how the Fast 102 lower lines up with the Trickflows.

Good thing is you know you can leave it if you want and know the car will still make great power. Nice job so far!

 

I cant help but notice how clean you got those pistons..HOLY SMOKES..what did you use?? Also, congrats on everything, you'll have it running it no time now..

 

On the Stock heads the FAST was overported thus having port mismatches on the sides and around the Cathedral area which was more
important. The Floor had a mismatch but it was not as bad as the TF.
Now the sides and the Cathedral are fine on the TF.
I know my friend made 526 RWHP/ 478 RWTQ and I know by his own words
his builder did not mess with the Trick Flows. As a matter of fact he exceeds the LS3 records. I talked to TF about these issues and they said they have no porting issues. I dont know if the Guy was A engineer
or a salesperson. I do have more questions but have no intent to modify the Floor of the TF. I will see what I get for numbers on my final Build.

 

This is a pic of a port matched application on a ported 243 head. I actually cut the runners with a head attached to perfectly match the surrounding lines of the head. There shouldnt be any metal seen as you look through the FAST's runners at the head's runner.

The lower left hand corner is just a glare. It lines up perfectly. I used to place each FAST bottom shell on a head and use a bearing topped bit to take out the last 1/2 inch of the FAST to match the runner exactly. Then I blend in the rest by hand.



The trick flow and AFR 205 have really wide runners. You have to dig in pretty deep to be seeing metal on the sides like that. You dug in a bit too deep Leon.

 

I know but I am considering A 102 FAST after giving it a Spin on the DYNO. I was overported on the FAST side. I cant believe I got the Dyno numbers I did and anyone would agree the port mismatch on sides cost
me some ponies. I wish I had A stock 102 in front of me or someone can give me a measurement. Maybe Ill try HINSON if they want to sell me one.
BTW did a static compression test W no oil in the cylinder and the gage went to 230. Then it broke. Never seen a number like that. At least the Head gasket sealed. LOL

 

HOW MUCH DID YOU MACHINE FROM THE HEADS??
I went to 61cc and was at 12.1 or so, and DCR was 8.7
230 sounds good to me!! Compression is your freind!!

 

Phil, Just got finished the Yella Terra's. Sure looks good. I did talk to TRICK
FLOW Engineering and the raised Floor is intentional and they were asked that question 1,000 times. He emphasized the need for room in the cathedral area and the sides should port match. My problem was overporting of the FAST. I have some mismatch on the sides and Im not going to remove material from the TF HEADS.

BTW. Their was .035 removed on a straight cut from the TF's thus arriving at 59.5CC Chamber volume.

 

So the TF engineer said, essentially, we built that ledge on purpose, don't change anything?

 

A positive step in the direction of flow is never a good thing. Even a negative step is not great, but much better than a positive step. I can't believe that the TF guy said to leave it alone.

 

Spin covered some of this in another thread, it's hard to believe!
will a new 102 fast allow a match?

 

the pictured step doesnt' look like it would hurt much NA, since the motor is sucking the air in. now in a FI application, where its forcing air and it smashing into the step, would cause more of a disturbance

 

Holy crap, 2 years later LS1 tech bashed me for this, Spin took my comment way to personally

Sorry Spin, if you didn't care so much about your work, I would have never posted anything. But since you care so much I wanted to share some info!!!

Thanks guys
Randy
PS Don't use scotchbright

 

Actually, don't let sucking versus blowing fool you. It's just flowing air. In the FI case it's higher density air so you are right it's worse. But even with NA air (slightly below ambient when at WOT) a positive step still is terrible for good air flow.

 

Actually I cleaned the Tops of my pistons with Rags soaked in Lacquer thinner. It came off like melted choclate. I got the idea from Glass Slipper
and did use Scotchbrite to get some stubborn spots. Yes it does powder off but A high pressure blast around the ring area blasts it out onto a Damp cloth. Scotchbrite is fine and not abrasive, its the cleanup
afterwards to get the particulates out of the cylinder. I wish there was a better way to get the Coolant out of the holes in the block. It took a full day just for cleanup and probably after 100 miles the tops of the pistons will discolor again but I wont see it.

 

If anyone finds a good way of not making a mess blowing out the head bolt holes in the block. Please share

The best way of keeping the tops of the pistons clean is to run it at WOT often and for extended time!!!

Randy

 

Youre not looking at all the variables. While its true the positive step is hurting things, the gain you get from cutting on the head, then hurts the velocity in the head's runner by making it slower. Just like on an aircraft's wing, the speed the air is moving is critical to the performance.

In the situation of the head's floor, you are essentially changing the angle of the short side radius and making the floor of the runner longer. You increase the heads runner volume too and its at the entrance to the runner which is the worst place to do it. Then after the runner is opened, the air must be compressed as it approaches the intake valve because the height goes from taller at the head's intake, to shorter at the valve. This height compression is just as bad as the port's positive step because of how close it is to the short side radius. Its actually less offensive back by the entrance and nearly irrelevant if its 1" prior to exiting the FAST's outlet.

Your net gain is negative at best and it could be substantial. I'd say you gain 3HP from leveling the runners' floors and you lose 5-7HP from messing with the floor of the head's runner forcing the air to then have to compress as it travels through the runner.

The correct course of action is to build up the floor of the FAST 92 or 102 which ever is the case, and then they will be level with each other. In fact, its optimum to match the exit of the FAST to the head because it straightens out the air's exit angle from the bend in the runners. It would make more TQ because you made the cross section of the runner less with respect to its length. Also having less angle, part driveabiltiy would improve from a stable airflow that is neither compressed or widened.

I can do that with JB Weld. Anyone interested in doing this as an experiement and wants to get some input from me, please send me a PM.

 

Excellent info (again). I kind of thought that opening the port on the head was probably the wrong thing to do because of velocity changes. I agree, he needs to build up the manifold, but is there anything you can use that you can trust will not come out in the future? I like JB weld, but I've had it age and crumble after a few years in an environment that was probably around 140 degrees F.

 

I just got done putting everything on except the FAST. Here are the final pics on the torqued heads. I will torque the manifold down later tonight when I get 2 1/2" bolts to get a better view. Check it out. Definately
overported here and will talk to porter about my situation.