Hey Dan, question about gutted upper intake.

I noticed in the "showroom" you said you had a gutted upper intake (very nice car by-the-way). I am in the process of polishing and porting my intake and was wondering did you lose a lot of low-end torque by doing the gutting job? I know you are supposed to gain more power on the top end by doing this but was wondering what a difference you noticed on the lower end? Thanks, Jeff P

Not Dan here. I also gutted my upper and while I'm still fighting an vacuum leak, I'm going to offer that it does have an affect on low end torque. I think we kind of get enamoured with the bragging rights that go with saying we have a gutted upper. If all out top in performance is what your after for the drag strip, then gut it. If the car is a daily driver, primarily,or you want to auto X it then you may want to consider alternatives. I am probably going to do another one where only two sides of the web are removed, based on the firing order of the engine. I believe this may be a satisfactory compromise between shear volume and maintaining velocity in the flow. I have ridden in Dan's car and it seemed strong down low. Remember his is a 2.5 stroker which would tend to mitigate the effects of the gutted upper.

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88 TC X 2, 86 SVO, Main TC with K&N, 3"DP to 2.5"duals through Dynamax, Ric valve at 17+ and disconnected KS.
Elite Bodega 16" chrome wheels. Autometer pod w/ A/F and Vac/boost gauges. New engine shortly, ported head and
manifolds, polished and cc'd chambers, A-230 cam, Race Engineering Adj Cam Sprocket, Crowlers, ARP head studs, Walbro 190 pump and T-3 for starters. KB subs
and jack rails.

[This message has been edited by Pete D (edited 06-06-2001).]

Pete: Can you be more specific concerning what you said: "do another one where two sides of the web are removed based on the firing order of the engine". Maybe I'll take your experience and try it your way if I can understand how to go about determining which two of the four runners to remove and would you go all of the way from one end to the other or stop at a certain point?

Jeff

Actually I haven't noticed a low end loss, however, as Pete mentioned, I have a longer rod / shorter piston .030 over combo (not actually a 2.5 stroker though...which uses a 2.5 crank). Also have a Ranger Roller Cam.

If anything, I feel that my set-up has more low end torque than before.

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Dan Eaves
88TC 5spd, Shortblock with Crower 5.5" Sportsman Rods and Short Wiseco Pistons bored .030" Over, Ported Head with Polished Combustion Chambers, Gutted & Polished Upper, Ported & Polished Lower, Polished T/B, Ported E6, SVO T3 Turbo, 3" DP w/No Cat, RR Cam, Adjustable Cam Sprocket, K&N in Fenderwell, Gillis Boost Valve, Centerforce I Clutch, Removed A/C, Polished Wheels, Polished Valve Cover, Polished Crank and W/P Pullies, and the DAMN Heater Core is new too !

Jeff, I heard about the "half gutted" manifold from a guy on another board that did one. I need to get more info. As I said it's based on firing order so I assume that the webs being removed would be between the runners for 1 and 4, and 2 and 3 since the firing order is 1,3,4,2. This way there is one crankshaft revolution inbetween shared runner cylinder's compression strokes.
I don't have any actual experience with this setup yet. I tend to lean toward the camp of those that feel the big gains are made on the exhaust side (ported E-6, ported exhaust side of the head, larger exhaust valve) for engines that are primarly for street use. The turbo is capable of overcoming some obstacles on the intake side and good low end torque is, in part, dependent on the velocity of air flow into the cylinder. The gutted upper slows down this flow velocity. Many just clean up the runners in the upper and leave it at that. There are some gains to be made in the intake valve pockets in the head. There is some nasty restrictions and shrouding in the pockets. The intake valves are also badly shrouded in the combustion chamber and putting in larger intake valves only makes the problem worse. Water jackets limit how much the valves can be unshrouded. This thinking changes for all out engines. Then oversized intake valves and gutted uppers or even custom intakes have added value. It's important to know what kind of HP you are aiming for and what the primary use of the engine will be. Another consideration is the possibility of having to cut and re weld the upper in order to work on the runners.
Also bear in mind that the ranger roller cam is a very mild cam (.390 lift). It advantages are the reduced friction of rollers, longer life (rollers) and possibly an emphasise on low end torque where most trucks need it. It does not have enough lift to support the high end rpms where the gutted upper would really benefit. (I'm not saying there isn't some benefit here, just that it won't be maximized) Even the Motorsports A-230 that I'm using (.420 lift) isn't tall enought.
The vacuum leak in my new engine is certainly affecting my low end response, but how much I don't know till I get it fixed.And remember that I am used to the 235 HP that I was getting from my old engine with the quick response of the IHI. I'm still running relatively low boost levels until I get some more miles on the engine and get the larger fuel pump in.

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88 TC X 2, 86 SVO, Main TC with K&N, 3"DP to 2.5"duals through Dynamax, Ric valve at 17+ and disconnected KS.
Elite Bodega 16" chrome wheels. Autometer pod w/ A/F and Vac/boost gauges. New engine shortly, ported head and
manifolds, polished and cc'd chambers, A-230 cam, Race Engineering Adj Cam Sprocket, Crowlers, ARP head studs, Walbro 190 pump and T-3 for starters. KB subs
and jack rails.

I removed my gutted lower to work on it. I think you loose some low end. I can't feel a big difference between the 2. The general consensus with Turbo owners is that you loose a liitle on the lower end. I'm not to sure that you gain much by gutting the upper for that matter.

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85 TC 5 speed, K&N filter charger, Ranger Roller cam, 3" exhaust system, manual boost valve, large VAM, SVO PE computer, front mount intercooler, underdrive pulley, ported upper and lower intakes, 245/45/17 wheels & Tires