TPI Cross Ram Construction Thread
#51
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Re: TPI Cross Ram Construction Thread
Not trying to pee on parades or anything, but wouldn't you be better off and less time/money just fabbing a sheet metal intake like one of the many that Hogan's make?
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Re: TPI Cross Ram Construction Thread
Hope you don't mind some constructive criticism. Looking at the angle of your runners where they will meet the cylinder head, I see almost a 70 degree difference between the runner exit and the intake port of the head. I would think it best to reduce this angle as much as possible. One of the key advantages with the cross ram concept is the natural reduction of this angle.
I will gladly take a small increase in angle here in order to have the injector pointed directly at the valve instead of at the floor, like most EFI manifolds have. I do like the port/injector configuration that the OP is going for.
Last edited by gregs78cam; 03-21-2012 at 12:23 PM.
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#57
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Re: TPI Cross Ram Construction Thread
Actually the intake flange is situated at 35* from horizontal. That puts the roof of the intake port at about 46* from vertical, which is just about the entry angle of the runner.
I will gladly take a small increase in angle here in order to have the injector pointed directly at the valve instead of at the floor, like most EFI manifolds have. I do like the port/injector configuration that the OP is going for.
I will gladly take a small increase in angle here in order to have the injector pointed directly at the valve instead of at the floor, like most EFI manifolds have. I do like the port/injector configuration that the OP is going for.
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Re: TPI Cross Ram Construction Thread
I haven't read anything on injector angle, but logic tells me that if it is pointed at the back of the valve and the spray hits the valve, the fine spray pattern may flood and kill the atomization of the fuel.
#59
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Re: TPI Cross Ram Construction Thread
Fuel atomization with port fuel injection is mostly created by the pressure differential between inlet air and fuel from the injector nozzles. The higher the nozzle pressure, the better the atomization, at least that's the theory. It seems to prove out in my experience. It's alot the same as the ventury in a carburetor, except that it takes place in the intake port of the cylinder head rather than at the throttle.
One factor that makes a real difference, at least in fuel efficiency at lower engine speeds is sequential verses batch fire injection. In sequential, the injector is firing when the intake valve is open and as the air is being drawn into each cylinder. With batch fire, the injectors all fire together every turn of the crankshaft. Meaning some intake valves will be open, others will not be. This means that at lower revs, the fuel in some cylinders is going to sit for a moment behind a closed valve before it's drawn into the cylinder. At low engine speeds, this will have a negative effect on efficiency. As engine speed increases, it has less effect since fuel droplets move at a constant speed while the engine cycles faster. At some point, the fuel and air are moving almost at a constant velocity past the valves and into the cylinders.
One factor that makes a real difference, at least in fuel efficiency at lower engine speeds is sequential verses batch fire injection. In sequential, the injector is firing when the intake valve is open and as the air is being drawn into each cylinder. With batch fire, the injectors all fire together every turn of the crankshaft. Meaning some intake valves will be open, others will not be. This means that at lower revs, the fuel in some cylinders is going to sit for a moment behind a closed valve before it's drawn into the cylinder. At low engine speeds, this will have a negative effect on efficiency. As engine speed increases, it has less effect since fuel droplets move at a constant speed while the engine cycles faster. At some point, the fuel and air are moving almost at a constant velocity past the valves and into the cylinders.
#60
Re: TPI Cross Ram Construction Thread
I have told this story before but worth the repeat. When I was going from a 3-bar fuel pressure to a 4-bar fuel pressure, as we were cranking up the fuel pressure the idle kept getting better and better. I am now run at 58psi of fuel pressure. Kevin adjusted the table accordingly.
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Re: TPI Cross Ram Construction Thread
With batch fire, the injectors all fire together every turn of the crankshaft. Meaning some intake valves will be open, others will not be. This means that at lower revs, the fuel in some cylinders is going to sit for a moment behind a closed valve before it's drawn into the cylinder.
With sequential EFI, it is not an issue.
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Re: TPI Cross Ram Construction Thread
I have always run 50-3 fuel psi. It always seemed to run a lil better than the next guys car..
#63
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Re: TPI Cross Ram Construction Thread
Of all factors to consider however, I think that the most important is a smooth path for air flow with as gradual bends as possible, if bends are necessary. Ideal injector angle, to my thinking, is secondary to this. Just my opinion.
As far as fuel pressure goes, the newer factory systems run as high 80psi.
#64
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Re: TPI Cross Ram Construction Thread
One thing I just thought of is the effect of spraying cool liquid on a hot valve. Could this cause warpage? If the fuel pressure was high enough, the fuel spray would atomize into a mist of fine particles. That might help prevent problems.
#65
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Re: TPI Cross Ram Construction Thread
I think that with an aluminum manifold absorbing heat from the engine, and the the heat that is created when the pressure is boosted, you probably don't get really cold fuel being sprayed on a hot valve.
#66
Re: TPI Cross Ram Construction Thread
Another update. We have cut up the runner material to size and they are ready to be welded together. After some careful measuring of everything I decided to go with 1.5 degree of taper. That is about as much as I can do and have everything fit. Here are some pictures of a runner with the two halves clamped to gether and one looking down the inside of the runner.
Last edited by 1989GTATransAm; 03-23-2012 at 11:15 PM.
#67
Re: TPI Cross Ram Construction Thread
The runners are now back from the welder. I am now down to 8 pieces from 16 halves. Next there will be 4 paired runners. Removing the exterior weld will be a peace of cake with the mill. The interior welds will test my skills. Here are a couple of pictures.
#68
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Re: TPI Cross Ram Construction Thread
Good to see the progress. I'm excited to see the completed assembly.
#70
Re: TPI Cross Ram Construction Thread
Took the base over to my friend Pat's house and we fitted it up to his long block. I wanted to see how the machined ports now line up with his AFR heads. It is looking real good. The angles look to be right on with the roof and floor of the AFR head.
I also held in place one of the new runners in the location it will be in and there is no problem looking right down the port at the back of the intake valve on port one. On port 3 you can see about a fourth of the intake valve because the port turns the other way. If a straight line means anything in a intake manifold runner this is going to be good.
I also held in place one of the new runners in the location it will be in and there is no problem looking right down the port at the back of the intake valve on port one. On port 3 you can see about a fourth of the intake valve because the port turns the other way. If a straight line means anything in a intake manifold runner this is going to be good.
#73
Re: TPI Cross Ram Construction Thread
I have the heads in my garage to open them up some and make sure they are as wide or wider than the TPI Cross Ram base. Then I thought it would be neat to take some pictures to get an idea where we are going with this. I proped up one of the runners in just about the position of where it will go and took the pictures. One of them is looking right down the runner into the back of the intake valve. Here are the pictures.
Last edited by 1989GTATransAm; 04-02-2012 at 06:22 PM.
#74
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Re: TPI Cross Ram Construction Thread
Wow! I can hardly wait to see this thing completed.
#75
Re: TPI Cross Ram Construction Thread
A little update. I have now paired the runners. Started with 16 parts and I am now down to 4. We did some more machine work to the base but here are a couple of pictures of the paired runners. By the way the welds on the corners will be machined squared and the material for the bell mouth will be welded on.
#76
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Re: TPI Cross Ram Construction Thread
I can really see it coming together now. I'm still curious to see the transition between the extruded tubes and the base.
#77
Re: TPI Cross Ram Construction Thread
The transition from the extruded runers to the base will be welded on the inside and some on the outside. I will then hand grind what I need to make a smooth transition between the two parts. The more I think about it this intake has a lot of potential. The dyno results should be interesting.
#78
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Re: TPI Cross Ram Construction Thread
"The dyno results should be interesting"
I just hope the engine you choose to dyno your Cross Ram with will be able to do your Cross Ram justice.
You should know by this Friday afternoon, a little bird tells me
Talk to ya soon.....
I just hope the engine you choose to dyno your Cross Ram with will be able to do your Cross Ram justice.
You should know by this Friday afternoon, a little bird tells me
Talk to ya soon.....
#79
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Re: TPI Cross Ram Construction Thread
This manifold will definitely support top end power, assuming the plenums have adequate volume to allow the runners unobstructed air flow. The interesting thing will be to see it's torque curve and how well it supports low to mid range torque. I'm hopeful to see a very long, flat torque curve. I would say you certainly want a cam and heads that will support 7,000 rpm for this bad boy.
#81
Re: TPI Cross Ram Construction Thread
The results were interesting. 576HP on the engine dyno. Hmmmm, that will really put my TPI Cross Ram to the test. I doubt if it will match that.
Anyways I have a couple of pictures to post showing where I am at on the base with everything lopped off. Should have updated pictures of the runners next week. Found out something interesting. The new EV6 injectors are only 48mm tall or about two inches. Using them would simplify this project and allow me to increase the plenum depth. I will have to look into it. Here are a couple of pictures.
Anyways I have a couple of pictures to post showing where I am at on the base with everything lopped off. Should have updated pictures of the runners next week. Found out something interesting. The new EV6 injectors are only 48mm tall or about two inches. Using them would simplify this project and allow me to increase the plenum depth. I will have to look into it. Here are a couple of pictures.
#83
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Re: TPI Cross Ram Construction Thread
The results were interesting. 576HP on the engine dyno. Hmmmm, that will really put my TPI Cross Ram to the test. I doubt if it will match that.
Anyways I have a couple of pictures to post showing where I am at on the base with everything lopped off. Should have updated pictures of the runners next week. Found out something interesting. The new EV6 injectors are only 48mm tall or about two inches. Using them would simplify this project and allow me to increase the plenum depth. I will have to look into it. Here are a couple of pictures.
Anyways I have a couple of pictures to post showing where I am at on the base with everything lopped off. Should have updated pictures of the runners next week. Found out something interesting. The new EV6 injectors are only 48mm tall or about two inches. Using them would simplify this project and allow me to increase the plenum depth. I will have to look into it. Here are a couple of pictures.
I was thinking that were gonna need some 36# ers now with the 576HP!
I wonder if the 36# injectors are gonna be enough???
#84
Re: TPI Cross Ram Construction Thread
Normally you would be right but this is a totally custom deal and I need the plenum to be as low as I can get it. The bottom of the plenum needs be .500" above the fuel rail so that I can install it and remove it. So the LS3 injector would allow me another 1/2 inch in which to lower the fuel rail and in turn lower the floor of the plenum a like amount.
I just happen to have a set of extenders for the LS3 injectors. With those they are still a 1/2" shorter than the Bosch 3 injector and 5/8" inch shorter than the original factory injectors.
I just happen to have a set of extenders for the LS3 injectors. With those they are still a 1/2" shorter than the Bosch 3 injector and 5/8" inch shorter than the original factory injectors.
Last edited by 1989GTATransAm; 04-29-2012 at 12:35 PM.
#85
Re: TPI Cross Ram Construction Thread
Pat, the next time we meet up I will show you what I am talking about. So let's not buy anything until I have a look see when I go back to the machine shop on Thursday. I have relocated the fuel pressure unit to fit under the drivers side fuel rail. So I will need clearance for that and that could put a hitch in things.
#87
Re: TPI Cross Ram Construction Thread
Westech is also set up for EFI and they have done lots of them and also with a lot of experience in that area. So when my TPI Cross Ram intake is done we will put it on Pat's 383 long block and take it out to Westech and see how she does. The 576 HP mark will be a tough one to match. That is down right awesome in any ones book.
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Re: TPI Cross Ram Construction Thread
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#89
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Re: TPI Cross Ram Construction Thread
576whp may be ok on 36LB injectors at higher pressures...but I'd go 42's to be safe if running 43psi pressure. My friend makes near 615hp on motor which is based on the 521whp it made..and its 42lb injectors are pretty high on duty cycle
#91
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Re: TPI Cross Ram Construction Thread
Lol. I just now noticed the pictures of the stripped down manifold base before the runners are installed. About what I expected. Not much left of that thing. Just coolant passages and a cover for the cam valley.
#92
Re: TPI Cross Ram Construction Thread
Right. I will probably remove some more material between the coolant passages and the cam valley cover. At this point I am feeling my way along regarding the base. It is easier and cheaper to remove material than to add some back.
#93
Re: TPI Cross Ram Construction Thread
Here are some pictures of the runners. They only need to be cut to length and some minor cleanup. They are pretty much done. Now to mate them to the base, get the correct angle and weld them in. Once that is done on to building the plenum.
#94
Re: TPI Cross Ram Construction Thread
Some very good news. I will be able to use the LS3 EV6 injectors. I was worried about the clearance for the fuel pressure regulator but it will clear. Also there is enough clearance for the EGR valve. This will simplify the construction of the plenum by allowing me to lower the fuel rails a 1/2 inch. Notice the new location of the factory fuel pressure regulator.
Last edited by 1989GTATransAm; 05-02-2012 at 09:00 PM.
#95
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Re: TPI Cross Ram Construction Thread
I don't think your cross ram will have any trouble out pacing a single carb setup. The limiting factor will be the engine's ability to move air. You are creating 8 balanced, ultra high flowing runners. Now you just need to attach plenums that provide unobstructed air flow to the runners and hopefully avoid any sharp angles or sudden changes in CSA. No single carb intake can match that. The Victor comes close but even it is a compromise of runner balance and physical limitations.
#96
Re: TPI Cross Ram Construction Thread
Here are a couple of pictures of the runners in place at one end. At this point the runners are 1.125" to long. They are going to be shortened by a like amount. Also a shot down one of the runners with more work to be done. Hopefully ASE doc you are correct with your assessment. Here are the pictures.
#97
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Re: TPI Cross Ram Construction Thread
Wow! Beautiful! That thing is going to look nasty. Of course you need to do some work on the transition where the runners meet the base. I've been thinking that this will be your key challenge. Making that transition smooth. So far it's looking great.
#99
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Re: TPI Cross Ram Construction Thread
I've been thinking about the throttle set up too. Several factory engines have used dual throttles, even the old 3.5 Chryslers had dual throttles. It would be tricky but the linkage could be adapted to this application. The key would be balancing the throttles.
#100
Re: TPI Cross Ram Construction Thread
The floor of the plenum will be about a 1/2" below the bellmouth entrances. It will initially be in two pieces with each piece cutout for the runners and slid in from each side and meeting in the middle. It will then all be welded together. The plenum will be supported by the runners. Once the plenum floor is in place the rest of the plenum can be built up and when it is all said and done it will resemble the Super Ram plenum.
Where the runners meet the base it will all be welded up internally and externally and then I will grind it out for a smooth profile with the correct cross sectional area. It will blend in nicely. It just looks rough at this point. I will be using the standard TPI style throttle body.
Where the runners meet the base it will all be welded up internally and externally and then I will grind it out for a smooth profile with the correct cross sectional area. It will blend in nicely. It just looks rough at this point. I will be using the standard TPI style throttle body.
Last edited by 1989GTATransAm; 05-04-2012 at 02:36 PM.