I'm heading to the dyno this weekend, for some tuning. I've never done this before and inorder to get the best bang for my buck, I'm looking for advice to make sure I don't waste time/money. Here's my thoughts, and my set up.
Take extra gaskets, plugs (gapped @.040), timing light (mine for future timing), 1in. wood spacer, carb tuning kit, carb gaskets, check air in tires, check for leaks, ensure oil fresh and full, check radiator level.
400 (bored storked 462 approx.) Edelbrock RPM Edelbrock Performer AVS 800 carb 9.5:1 compression 16 Heads Ported 240cfm NGK plugs .040 gap 5 speed Tremec TKO 600 3:42 posi Clutch 7 bladed fan Comp Extreme Energy 268XE cam. O-2 bung in passenger side exhaust pipe
Any advice on dyno tuning, or tricks I should try?
The motor was dyno'd with headers after it was built (on an engine dyno) and it turned 402 HP and 502 lbft of torque with an Edelbrock 850 Qjet. It has the 800 AVS and Ram Air LB manifolds now. I'd like to see the same or better. After the carb change, I now have the "seat of the pants" feel I've been wanting, but I know its running very rich. The cam is pretty mild, so we'll see. I wasn't there when the engine shop dyno'd the engine when it was built so all I have are the run sheets, but now "tuning knowledge". Who knows. If I can pull 400 HP at the rear wheels, I should be happy....but more is always better.
Tuned on the Dyno this morning. Very nice way to tune. Especially since where I live, I'd have to take a 10 min. drive just to get somewhere I could run the car above 30mph. Hot and humid, but I pulled 300 HP / 390 lb/ft at the rear wheels. Use a Mustang Dyno. I've always heard you lose 20% for the drive train. In my case a bit more, but this time I didn't have headers (LB manifolds instead), and I had a clutch fan vice electric water pump. Car has great seat of the pants, we'll see how she does when I fuel inject it in a couple of years.
Yep, that is what I'm leaning towards/been told by a few people. Car's going into storage after this year while I head overseas for 3 years. I'm planning a cam swap when I get back, along with fuel injection (maybe). Not sure which cam, possibly the Comp Cams 274XE (not sure off the top of my head if it is a dual pattern or not though). I'm also a bit concerned about loosing drivability if I go any larger than what I've got, that is the reason I went with the 268 in the first place.
The motor pulled 400HP on the engine dyno. Are you saying with a different cam I could pull 450 at the rear wheels? Thats a hell of change off a cam swap. I've been told I could add about 100HP from a cam swap, but was sceptical. I've listed my current setup at the top of the post, what cam do you recommend. Again, my goal was a streetable combo I can cruise 8 hours with. More HP would be great, and maybe I'll make the swap before I leave the country, just for fun. Recommendations? Thanks.
Contrary to popular belief, good flowing heads and a small cam will be more drivable than lesser heads and a bigger cam making the same power. It seems that you've already discovered that by the way the car feels. This is my preferred method of building an efficient, flexible and powerful engine. The newer engines coming out of Detroit are also following this formula.
Usually, a loss of driveability comes from a poorly coordinated engine package or poor tuning, not oversized ports - although that gets blamed when porting is mentioned. Most of the time it is because of an oversized cam and carb. They don't play well on the street! I see a lot of engines for sale with 500 - 1000 miles on them that have proven too much of a challenge to tune for the new owner. Usually a step or two back on the cam will fix the problem.
If the rest of your combo has the ability to flow sufficient air to make the hp and the cam is the only component holding the combo back, yes, the cam change can net you a fairly large gain in horsepower and also in torque, depending. Since you haven't listed the exhaust port flow numbers or the rest of the intake numbers, it's reasonable to assume that you haven't altered the port balance that much, and a dual pattern cam should be a better match for your combo, especially without headers.
Just did a back to back dyno session with two purpose built engines, one with parts spec'ed and provided by the customer, the other by me, for the same racing class. The first one was adequate, about on par with several other engines in the class but hampered by the cam choice. The second was a better coordinated package with the cam being noticeably better than the first one. The result: the second engine produced 12% more torque at 3500 rpm and - ready? - 45% more hp at 5800 rpm! A little more than would usually be seen!
Like Tom says, you can get a fairly big chunk of hp in the upper end of the rpm range by changing the cam to the equivalent of the RA IV cam. 450 hp should be within reach and shouldn't adversely affect your cruising enjoyment.
Fuel injection lets you go a bit farther with cam choice and still retain driveability. To illustrate, an engine that I did last year was essentially the same as the above mentioned two engines, but with more compression, bigger cam and aftermarket fuel injection for a different racing class. Produced an addition 46% hp over the best of this year's two engines but still idled at 1000 rpm and had excellent manners, very civilized. Again, don't expect this large a gain on a street engine but if you build the engine as a package you can make excellent power and still live with it.
Fuhrmann, just caught the question you asked a couple of posts ago, sorry. I like the 3:42s, I would have gone a bit larger if I had planned to put the TKO 600 in, but a the time I was planning on a built T400 so no overdrive. I bet you'll like the 3:55s, although the 3:42s are great. I finally got a chance yesterday to take it out an bang the gears on a nice secluded street, and I was not left wanting.
TOHcan, I'm going to leave the cam as it is now, but will make a change when I get back from overseas at the same time I go to fuel injection. Here's some more info on my setup, maybe you can recommend a cam for me. The heads were mildly ported by Dave Bisschop at SD Performance. They're his 240cfm package, not sure the specifics, but I think I've got the sheets at home if it helps. Also the intake, nor exhaust manifolds have been matched to the heads, so they are unaltered. When I go to the EFI, I'll be swapping to a Torker II manifold (EFI ready), and I may port match them if that would be advantageous. Thoughts?
450 hp at the flywheel as you noted, Jim. I'm sure that's what Tom was meaning as well. My modem decided to bail before I could edit and clarify, just got it going again.
What computer are you going to use, and who will be doing the tuning? What exactly are you after with your package? Sounds like you're keeping it on the mild side but understandably don't want to miss out on any fun! More cam = less fuel mileage in any combo, if that's a concern.
To clarify on the porting vs driveability, usually porting is perceived as a race only mod, and the cam is selected accordingly. Poof! There goes the low and mid range! Porting the heads increases the amount of air flowing at most if not all valve openings. The cam determines how the engine runs in the various rpm ranges and whether it leans towards street or race characteristics.
The amount of porting needed to significantly alter the volume of the intake port and thereby decrease air flow velocity (which can make the engine a bit lazy in the lower ranges but not necessarily) is - a lot! More air through the engine is good. More displacement is good. Neither automatically causes the engine to fall flat on its face or lose driveability.
Your cam is a good match for this combo for mostly street with some strip use, as the ramps are very aggressive for it's advertised duration. But as Claus said, you should be using 1.65 rockers.
However, if you plan to inject later on, that 110 lobe seperation angle (LSA) is going to make it difficult to get a clean map signal. For EFI you need more like a 114 LSA. Shoot for somewhere between 224 and 234 degrees intake and another 8 or more degrees longer duration on the exhaust. The Summit 2802 should get you there with 1.65 rockers. Keep that in mind for your next cam swap.
I'll most likely be going with a Butler set up EFI. He's using the FAST system and Edelbrock Torker Manifold. Spoke with Chase there today and he said since the system is so adjustble, you can run almost any combo on it and it'll work well. They take the motor specs and planned desires and create an initial MAP Burn (right terminology?) for it and it should run pretty well. Then after driving a bit, I can make the needed adjustments to dial it in. It will be 3 years before I do this upgrade, so who knows what will be available then, or what won't be. The 1.65 rockers sound interesting. We'll see if I can stay happy with what I have for the 6 months I have left driving the car.
I'll most likely not make any changes till I switch to FI, just didn't think about the rocker arm switch. I'm still new to the motor work, atleast the technical side of it, so I always check with a good builder before I do anything. Bjorn, what does moving to 5/8" push rods do except add strenth?
I think the 1.65 rockers move slightly more around in the hole, and You need to give more clearance....THOCan might know the impact...Quenton told me to do it...and its not the push rods that are stronger...but you`ll need new ones too, b/c the length changes... ( I think)
Push rod length and diameter will not change. You use your existing pushrods. The hole through which the rod passes in the head will have to be enlarged, as Bjorn said. Its not just a "bolt on" upgrade. As mentioned by others, you have to check alot of other details...
I'm a hobbyist. Not a professional. Don't be hatin'!
The pushrod socket is closer to the rocker arm pivot in order to get the higher ratio. That moves the pushrod closer as well, and clearance must be checked to make sure things aren't rubbing!
The pushrod socket is closer to the rocker arm pivot in order to get the higher ratio. That moves the pushrod closer as well, and clearance must be checked to make sure things aren't rubbing!
thanks for the explanation Brent!
and I bought new push rods too , since they were not expensive (-$20)and might as well put new in as it was apart...
