TTA vs GN head comparison.

[Hi-psi]

Tooks some pics of a TR head and a TTA head from the same angle so as to see the differences, and possible more efficient TTA design. Notice on the TTA head how the spark plug is angled towards the intake valve. Also notice the non-round shape of the TTA bowls. This means more head deck surface which may lead to a less likelyness of a TTA headed motor to blow head gaskets. Thoughts?


TR head:

http://hi-psi.netfirms.com/stuff/41motor4.jpg

TTA head:

http://hi-psi.netfirms.com/stuff/ttahead.jpg

 

[RobCrisafulli]

To see the real difference you should take some pics of the exhaust ports. The TTA flows better on the exhaust out of the box because the exhaust port is cut back furter into the head as compared to the GN head.

But this a disadvantage in the long run. The material removed means the head has less meat to help hold the head down under boost. This is why the TTA heads tends to push the head gasket out at the bottom of #3 and #4.

Also, the open chamber of the TTA head is better more volume the more air/fuel you can pack in.

Champion recently add more meat in the exhaust area on the GN1 heads. The more metal the less the head will give and lift. There 4-5 pounds heaver and their aluminum!!

I ran 30-32 psi in my TTA even with no knock, the head will lift and the gasket will erode from exhaust gases passing by it. Then its only a matter of time before it blows.

 

[SPower6]

Originally posted by RobCrisafulli
To see the real difference you should take some pics of the exhaust ports. The TTA flows better on the exhaust out of the box because the exhaust port is cut back furter into the head as compared to the GN head.

But this a disadvantage in the long run. The material removed means the head has less meat to help hold the head down under boost. This is why the TTA heads tends to push the head gasket out at the bottom of #3 and #4.

Also, the open chamber of the TTA head is better more volume the more air/fuel you can pack in.

Champion recently add more meat in the exhaust area on the GN1 heads. The more metal the less the head will give and lift. There 4-5 pounds heaver and their aluminum!!

I ran 30-32 psi in my TTA even with no knock, the head will lift and the gasket will erode from exhaust gases passing by it. Then its only a matter of time before it blows.

Rob-
Can anything be done in the way of better gaskets for stock ported TTA Heads?
Thanks,
Jeff

 

[Hi-psi]

Originally posted by RobCrisafulli
the head will lift and the gasket will erode from exhaust gases passing by it. Then its only a matter of time before it blows.

Wouldn't some of the heavy duty ARP bolts, or studding the block help to keep this from happening?

 

[bruce]

Originally posted by RobCrisafulli

Also, the open chamber of the TTA head is better more volume the more air/fuel you can pack in.

Actually that is a disadvantage.
The larger surface area allows for mor eheat to be transferred to the coolins system rather then recovering that energy to moving the piston.

All things being equal a smaller chamber is a better *thing*.

Using a relief in the piston under the plug area, maintains the same quench area in either case, but allows for mor heat enrgy to be recovered to moving the piston. If in doubt about putting too much heat into the piston in this design, a barrier coating and water injection would help

An interesting experiment would be surfacing the head to reduce the chamber size so the head wasn't as thermally loaded and see how the gasket sealing problem changes.

Also, all the iron heads need the chambers smoothed out to reduce detonation. Long term trace and tipin detonation will take it's toll

 

[RobCrisafulli]

I would recommend head studs, but you need to clearence the headers and change to small headed ARP stainless 12 point bolt for the headers. You need to mockup this up on the engine stand. It a slight mod, but required. If you do not want to do this good ARP head bolts is second best.

As far as head gaskets and my brother and I have run them all (no kidding here). I like to run a 14bolt head gasket because the gasket has more material on the bottom and resists blowing more for this reason. I would not worry about running big bore gaskets on small or stock bore motors. I guess my favorite gasket is the Victor 14bolt for a Stage motor. Next would be the Felpro 1000. Although, at high boost this gasket will wafer and tends to get air bubles under it after the head lifts and exhaust gas eats at it. I am not into lock wires.

 

[Hi-psi]

Well the 4.1 I'm putting together had alread been studded. It's a .030 over bore. I'm planning to run the Felpro 1000's. I'm not planning on running any mad boost. Probably no more than 25psi.

 

[TTA89]

Rob just curious what your car runs and how much boost do you run?

Thanks

 

[RobCrisafulli]

Which Rob?

 

[TTA89]

You Rob C

 

[RobCrisafulli]

Sadly, my first TTA has not run in years now. I used to run it in the NSCA EFI class. It has been sitting in the garage with a bare Stage II 4.1 into for a long time now. I have started to work on it again and hope to have it running by the end of the summer if I can ever stop playing with my other turbo cars.

The original TTA build up was Ruggles 210/205 cam, big valve fully ported and polished heads, pot matched intake, adjustable push rods, stock rocker arms, stock bore, stock pistions, arp main studs and head studs, port and probed headers, arp rod bolts, 72 pounders, TA63/ptrim, PTE.63 housing, TH dp, 2800 multidisk lockup, built 2004R, bank to bank felpro, MJ 17 row IC, Currie 9", 3.40 gears, ATR exhaust, denny's driveshaft.

The EFI class was an indexed, power to weight factoring. We had to weight 3650 for the 11.75 class. You could run no more than 1 second under your index so 10.75 was the fasted we could go. My car was built to run 10-40's - 10.50's on super kill 30 psi, VP C16 only. We used to run 11.0's @128 with 24/25 psi, 1.7's 60 foot in the EFI class. If you go to close to the index they refactor you and slow you down. I have a picture of the car yanking the front gatorback off the ground, no trans brake, 2800 stall converter.

The converter started taking a dump shortly after that, wonder why and the intake started leaking oil into number 6 hole so we were done racing for the year. Even with the converter dumping I would put 30 psi on it and it would run 131-132 mph.

I am actually finish up a similar build up on my festival car, it got a lot of the parts off the first car. These cars are a lot of fun.

Robert Crisafulli

 

[TTA850]

Rob,I was wondering if you have found more or less where the limit is for TTA heads holding boost and not lifting enough to erode the gasket?Also how many runs,on average,could you get out of a set of gaskets running 30#'s of boost?

I'm starting to think I should take a pair of headgaskets and a torque wrench with me to the track

Steve

BTW I put my motor together with the 1000's

 

[RobCrisafulli]

You can run low 11's and have a car that last for years, running every weekend at the track. Typically this would be 500-525 hp, good gas C16 and no knock. 20-23 psi. Boost depends on cam and turbo size.

Now you want to go 10's. Now you need 550-600hp. So you crank up the boost to 25-30 psi. If you have a lighter car that 60 foots good, you can go 10's with less hp. If you have a heavy car you need more hp.

My brother and I would change the head gaskets on our motors every winter. Run the car during the racing season and freshen up over the winter. First, we think nothing of changing the head gaskets on a motor. We do all the work our selves so its not a problem for us. Second you learn a lot by tearing down the motor. You may find oil system problems, port mismatches, wiping cams, etc. If you run any National events, it sucks driving 12 hours to blow a gasket during the racing season. I think its better to be prepared.

If you want to make your motor live the longest, do it a favor by making the car as light as you can, work on 60 foot so you get the best ET for the hp the car makes and tune the car carefully. Go at it easy sneak up on higher boost levels. Read the spark plugs they will tell you everything you need to know. If you are running 27 or more psi, I would change the head gaskets every year and keep and eye on the inside of the motor.

Robert

 

[BandAid]

some good info from yrs ago...

 

[turbows6]

Also, the open chamber of the TTA head is better more volume the more air/fuel you can pack in.

TTA heads are NOT open chamber heads. They are closed, heart shaped chambers. They are also smaller CC than GN heads.

 

[TT/Ameasap]

TTA heads are NOT open chamber heads. They are closed, heart shaped chambers. They are also smaller CC than GN heads.

He may have been wrong about that little part, but he was right on with the heads lifting. Both you and I have experiences what Rob was experiencing years ago. I dont even remember this thread and it wasn't even what I was initially looking for, but looks like Rob warned long ago. Julio, JD, Rob, Me, you, and a few more have had the same problem.