There was a time not that long ago, when engine dynos were considered a black art. Not everyone believed what the dyno had to offer and some felt dynos were nothing more than hocus-pocus. Aren't you glad we don't live in those dark ages? Dynos are everywhere now and the reality of dyno racing has become an art form of its own. We thought it was about time to have our own dyno mule so to test any and every part imaginable just to see what would happen. So we built a 355cid Chevy and crowned it Danger Mouse (DM), in reference to the fact that it will be risking its life just to test any hair-brained idea we might come up with.
FROM THE BEGINNING
From the outset we knew DM would see a lot of abuse and we've logged close to 2,000 full-throttle dyno pulls, along with countless, unmeasured others, all without major breakage. Such reliability can be only attributed to one cause, the best parts. When building DM we stressed selection of the highest quality components to ensure a very long dyno life. The World Products 4-bolt Motown block and complete forged rotating assembly from Lunati have performed flawlessly, helping DM produce consistent results month after month after month, and we thank them for it.
Basically what we've learned in over 2 years of back-to-back testing is how to get a street small-block to produce anywhere from 300 to 700hp. All of it on pump gas, on a real world budget, and all with easy to find, off the shelf parts.
Danger Mouse is a mule built for dyno abuse, so we couldn't skimp on its parts. Heavy-duty
Since no dyno test would be worth diddly without baseline power figures to compare to, the first test for DM found it equipped with the barest of bone-stock top end parts. A pair of reconditioned iron "Camel hump" heads (casting No. 461) from Powerhouse Engine Components breathed through a cast iron GM intake fueled by a professionally rebuilt Q-jet from the Carb Shop. After we felt we had a reliable stock baseline (Test 1) to compare figures to, we dove head-first into testing all sorts of cams, cylinder heads, carbs, rocker arms, spacers, headers, superchargers, EFI systems, and intake manifolds, because that's what we felt most of you would like to see. We've learned a lot from these tests and are sure we'll learn plenty more.
Note: You'll notice that some test numbers are missing from this story. With 36 documented dyno tests completed so far, we feel that the results of some of them just aren't worth taking up the limited space we have here, so we're leaving them out. Don't worry, the results in those tests were pretty boring anyways. Also, to keep testing accurate and the results repeatable, other than the parts listed, nothing else was changed and none of the parts were ever modified for each test
Max 395 tq, 308 hp
Avg 376 tq, 266 hp
9.4:1 cr, No. 461 "Camel Hump" heads, COMP Cams 246PE cam (246/263 adv duration, 203/212 duration @ .050, .429/.438 valve lift, 110 Lobe separation), GM iron intake, Carb Shop Q-Jet, Proform HEI, Champion No.14 plugs, 91 octane, 37 degrees advance, 1 5/8-inch headers, 3-inch mufflers. This represents what a typical 355 cid small-block would make if it had just been blueprinted, but still used most of its stock components.
Test 2-New intake manifold:
Max 394 tq, 325 hp
Avg 380 tq, 270 hp
Installed a Weiand dual-plane intake manifold (PN 8004) and leaned out the Q-jet a bit. This netted us a 17hp gain.
Test 3-Roller-tip rockers:
Max 404 tq, 342 hp
Avg 390 tq, 278 hp
Replaced the stock stamped-steel rocker arms with COMP Cams Magnum 1.5:1 roller tip rockers, which gave us another substantial increase in power, raising peak hp by 17 and peak torque by 10. This pushed max tq over the 400 mark for the first time. Average hp and tq also improved over the stock baseline by a factor of 12 and 14 respectively.
Test 4-Retard cam:
Max 405 tq, 349 hp
Avg 390 tq, 278 hp
Retarded the cam 2 degrees, which added a little more peak power while averages stayed equal.
The next series of tests went a little deeper into the bolt-on field, but still kept swaps fairly simple. We made some improvements in torque this time, but horsepower gains were not that impressive.
Test 5-1 ?-inch headers:
Max 407 tq, 351 hp
Avg 388 tq, 287 hp
We installed larger 1-? Hooker headers. Compare tests 4 and 5 and you'll see that average torque was down by 2 lb-ft, but peak toque & horsepower were up slightly and average horsepower increased by 9. That's a fair trade to us.
Test 6-Full-roller rockers:
Max 407 tq, 351 hp
Avg 389 tq, 288 hp
Swapped COMP Cams 1.5:1 full roller aluminum rocker arms. Peak and average power increased by 1 each and we got 5 more lb-ft of torque at 3,200 rpm.
Test 7-XE256H cam:
Max 413 tq, 357 hp
Avg 396 tq, 293 hp
Swapped COMP Cams XE256H cam (256/268 adv duration, 212/218 duration @ .050, .447/.454 valve lift, 110 lobe separation) 2-degrees advanced and were rewarded with lots more grunt.
With Danger Mouse, we've tested everything we could think of, from easy to bolt-on headers
While the Q-jet carb had been working ok until now, we wanted to test a Speed Demon carb on a new Edelbrock Performer RPM "Air Gap" manifold. We also bumped up to the next size larger COMP Cams Xtreme Energy camshaft. The final reward was a new max 386 hp and 438 lb-ft of torque with new averages at 316hp/416tq. So now, we had this stock iron-headed 355 Mouse making almost 390hp and 440 lb-ft of torque! This was definitely the best power formula with the stock heads, particularly since the motor didn't respond very well to the bigger XE262H cam in Test 12. We took that as a sign that we had just about maxed out the stock cylinder head's flow potential and would either have to go in to start porting and polishing, or install a new set of performance cylinder heads for more power.
Test 9- Speed Demon 750 carb:
Max 418 tq, 356 hp
Avg 398 tq, 294 hp
Installed Speed Demon 750 and picked up torque and horsepower all around.
Test 10-"Air gap" manifold:
Max 438 tq, 380 hp
Avg 416 tq, 315 hp
Installed Edelbrock Performer RPM "Air Gap" intake manifold, which was the best single-gain swap yet and the first test to average well over 400 lb-ft of torque.
Test 12-XE262H cam:
Max 438 tq, 386 hp
Avg 416 tq, 316 hp
Swapped in larger COMP Cams XE262H cam (262/270 adv duration, 218/224 duration @ .050, .462/.469 valve lift, 110 lobe separation) straight up and low-end power began to fall.
EFI was found to be a very tunable way to make awesome power and we've had a lot of fun te
THE GENERAL'S PARTS
Dm needed some new heads and for our next set, we went to GM Performance Parts (GMPP) and got a set of iron Vortec castings. When compared to the stock "Camel hump" heads, the Vortec's actually dropped DM's compression by about ?-point to 9.25:1, but that didn't stop them from making 23 more horsepower. After that, we swapped also on our first set of 1.6:1 ratio rockers and were again rewarded with more power
Test 14-GMPP Vortec heads:
Max 435 tq, 409 hp
Avg 413 tq, 330 hp
Installed GMPP Vortec iron heads (Scoggin-Dickey Performance Center PN SD8060A: 64cc chambers, 170cc intake runner volume, 1.94/1.50 valves), COMP 1.5:1 Magnum roller tip rockers, and Edelbrock Performer RPM "Air Gap" manifold and made lots of extra power.
Test 15-COMP 1.6:1 rockers:
Max 440 tq, 416 hp
Avg 417 tq, 333 hp
Installed COMP 1.6:1 Magnum roller tip rockers, which further pushed the power curve up.
ROCKERS AND BIGGER CAMS
There's a lot of power to be found in rocker arms and camshafts and in that pursuit, we forged onward, testing yet another bigger cam and we swapped rocker arms until we were blue in the face.
Test 17-COMP 1.6/1.5 rockers:
Max 442 tq, 414 hp
Avg 419 tq, 335 hp
We wrestled rocker arm ratios around for quite a while and found that 1.6:1 ratio intake and 1.5:1 ratio exhaust were the best combination of all rockers tested until that point. They gave a torque improvement with no hp loss. Looking back now, Test 17 may have been the best overall combination of power and torque. Especially considering that these parts are all still low on the cost scale.
Test 18-XE268H cam:
Max 439 tq, 427 hp
Avg 418 tq, 335 hp
Next in went the next bigger COMP cam and we changed all rockers back to 1.6:1. We got the results we were expecting, more horsepower upstairs and less torque downstairs. We also tried this cam with the 1.6/1.5 rocker swap and got less power. (XE268H = 268/280 adv, 224/230 @ .050, .477/.480 lift, 110 LS)
No question, most of the swaps we've done have involved the valve train and we've run a lo
After the strong normally aspirated baseline had been established, we began our long quest to build the most power possible on pump gas by first using a small Weiand supercharger. This little two-lobe blower made our 355 think it was a 502! Beginning with Test 19 we also installed our first set of aluminum heads too. The Trick Flow Specialties (TFS) castings lowered DM's compression to a more blower-friendly 8.5:1 and gave us some extra breathing room with their large ports. To see how much power the blower would add, we baselined the engine with the TFS heads, Air Gap manifold, Demon carb, and a new COMP Cams NX flat-tappet hydraulic camshaft first (Test 19), then bolted on the blower (Test 20).
Max 434 tq, 444 hp
Avg 401 tq, 340 hp
8.5:1 cr, TFS heads (Summit Racing PN TFS-30400013-CNC, 72cc chambers, 195cc runners, 2.02/1.60 valves), Edelbrock RPM Air-Gap manifold, COMP NX274H camshaft (274/292 adv dur, 230/244 dur @ .050, .487/.501 lift, 113 LS). COMP Cams 1.6:1 roller rockers. The lower compression and large camshaft didn't seem to hurt too much. In fact, it had some serious top end pull making 444hp at 6100 rpm. Low-end torque fell off, but we expected that since we were running a big cam combined with very low compression.
Test 20-Weiand blower:
Max 574 tq, 602 hp
Avg 539 tq, 462 hp
Installed the 177ci Weiand Pro-Street mini-blower, Holley HP950 supercharger carb out of the box, 36 degrees total advance, 100-octane unleaded pump gas and a can of octane booster. We offered a warm welcome to Mr. 600hp on this pull!
Right after the blower tests were completed we moved to electronic fuel injection. We heard that Edelbrock was making a new EFI manifold based on its Victor E casting and thought it would be a perfect match for the a F.A.S.T. EFI system we'd wanted to run. But, like always, we had to know how much power the engine would make with a goo-ol' carb first. So we equipped DM with a prototype COMP Cams EFI hydraulic roller camshaft and a Speed Demon 750 carb with corks plugging the fuel injector bosses and made a pull (Test 21).
Test 21-Carb baseline:
Max 430 tq, 474 hp
Avg 397 tq, 330 hp
TFS aluminum heads, Edelbrock Victor EFI manifold, COMP Xtreme Energy EFI prototype HR camshaft (281/288 adv dur, 230/236 dur @ .050, .544/.555 lift w/1.6 rockers, 113 LS). COMP 1.6:1 roller rockers, Speed Demon 750 carb, 36 degrees total advance. When compared to previous normally aspirated Test 19, DM's horsepower went through the roof! Peak jumped by 30 to an outstanding 474hp but torque fell off down low, so the extra power wasn't a freebie. COMP attributes the low-end losses to the more-aggressive ramp profiles on the NX274 hydraulic cam used back in Test 19. The hydraulic roller cam in Test 21 really begins to take over at higher rpm due to its reduced frictional losses.
Test 22-F.A.S.T. EFI w/ 30 lb./hr. injectors @ 50 psi:
Max 431 tq, 480 hp
Avg 400 tq, 332 hp
Installed the EFI system with Accufab throttle body and right away the EFI proved its superiority by bringing low-end torque back up and increasing top-end power to 480hp. Although power dropped slightly in the mid-range, which we think we could've recovered with some more tuning time.
REBUILD, REPAIR, AND RE-TEST
Throughout all this we've learned that no matter how tough you build an engine, there comes a time when it will need to rest. So after Test 22 DM went back into the shop for a complete overhaul by the technicians at Speed-O-Motive and came out equipped with some new bottom-end components ready for battle. The first series of tests following the rebuild were pretty uneventful and mostly confirmed that the rebuild did not cost any power. Besides, we wanted to go in a different direction with this rebuild and test some more low-end power making products because we felt DM was already getting too far out of reach for many. So you'll note that power is way down compare to Tests 21-22.
Test 29-Freshly rebuilt with some new components:
Max 415 tq, 399 hp
Avg 397 tq, 316 hp
Installed World Products Sportsman II angle-plug iron heads (64cc chambers, 200cc runners, 2.02 intake valves, 1.60 exhaust valves) @ 10:1compression, Holley dual-plane intake manifold, HP750 carb, Lunati hydraulic roller cam (215/224 @ .050, 268/279 adv, .489 lift, 112 LS), COMP 1.6:1 roller rockers. Also note: the following tests were done at a different dyno facility, so the results are not quite comparable to previous tests.
We've tried to match top end packages based on performance and found a lot of power in hea
Immediately following our less than exciting low-end power building exercise, we got our hands on one of ATI 's Procharger D-1SC centrifugal superchargers, which definitely gave us the "most power on pump gas" yet. For the blower bash our champions of the dyno and wrench, Speed-O-Motive, also dove back into DM's storage locker and pulled out the same old set of TFS aluminum heads we'd ran before. Speed-O also installed a new Crane Cams hydraulic roller with lots of lift and duration and then they topped it all off with an ACCEL GEN VII DFI system for the utmost in tunability. You may also note that compression is up slightly when compared to the other blower tests using the TFS heads, (Tests 19-20). That's because during the rebuild, Speed-O-Motive installed a new set of Lunati flattop pistons with a taller compression height, moving the piston top higher up the bore for a true "zero" deck. Previously, the old pistons were installed about .040-inch below the deck to better simulate what might really be under you hood. But, by this time we wanted to truly optimize everything.
Max 424 tq, 466 hp
Avg 393 tq, 333 hp
9.1:1 cr, TFS aluminum heads, Accel Gen VII DFI w/ 55 lb/hr, Crane Cams HR camshaft (240/248 @ .050", 306 /314 adv, .595 lift, 114 LS), COMP 1.6:1 rockers. Left the blower belt and induction plumbing off to baseline DM without any boost.
Test 32-ATI blower:
Max 613 tq, 697 hp
Avg 545 tq, 471 hp
Installed ATI Procharger D-1SC centrifugal supercharger with 4.25" pulley and got 697hp and 613 lb-ft of torque, all on 91-octane pump gas.
OLD FASHIONED POWER
Right after the blower test we moved back to making power the old-fashioned way, on the motor, and got this little beast up to some pretty big power figures.
Test 34-Vic Jr. heads, COMP XR280R cam:
Max 441 tq, 504 hp
Avg 404 tq, 359 hp
Next we tried Edelbrock's Victor Jr. heads @ 10:1cr, (64cc chambers, 215cc runners, 2.08" intake valves, 1.60" exhaust valves), with a Vic Jr. manifold and one of COMP's Xtreme Energy Street Roller camshafts (242/248 @ .050, 280/286 adv, .600/.606 lift w/ COMP 1.6:1 rockers, 110 LS), and a 650cfm Mighty Demon 650 carb. The results were 504hp and 441 lb-ft tq!
Test 35-Total Seal rings:
Max 453 tq, 497 hp
Avg 413 tq, 366 hp
This one was all about sealing. Total Seals' gapless top rings were installed and power and torque was increased up to 6,000 rpm. Average figures also climbed as well and some more tuning time probably would have gained us back the top-end power we lost.
Blowers have been a healthy part of Danger Mouse's diet. With this street-legal ATI Procha
THE BIGGEST AND BADDEST YET
The last tests got us thinking that bigger could truly be better. So, after acquiring an Edelbrock Super Victor manifold with an even larger COMP roller, we went back to see if we could break the 550hp barrier. Well...DM certainly made more power than it did the month before, but the results were a far cry from spectacular. After swapping the cam, intake, and carburetor, we saw an 11hp peak increase and 2 lb-ft of extra peak torque. While we're certainly not putting it down, for the time, effort, and expense of the swap the results were not worth it in our minds. All that means is that we've pretty much hit the wall with the current parts combination and just like on the street, throwing bigger parts at it won't make it go any faster. So we're rethinking our strategy and planning some cool stuff for DM's future. We're confident we'll see close to 600 N.A. horsepower soon, and still on pump gas too. One thing we know is that it won't be easy. But, it'll sure be fun!
Test 36-Super Vic, COMP XR286R cam:
Max 455 tq, 508 hp
Avg 420 tq, 365 hp
Swapped Edelbrock Super Victor manifold and COMP XR286R solid roller camshaft (248/254 @ .050, 286/292 adv, .606/.612 lift w/ COMP 1.6:1 rockers, 110 LS), Holley HP1000 carb, 38 degrees advance.
|Test 1 Stock Baseline||Test 2 Weiand 8004||Test 3 COMP 1.5 rockers||Test 4 Retard cam -2 degrees |
|Test 5 ? Headers||Test 6 Full roller 1.5 rockers||Test 7 COMP XE256H |
|Test 9 Speed Demon 750||Test 10 Air Gap intake||Test 12 COMP XE262H |
|Test 14 Vortec heads||Test 15 COMP 1.6 rockers |
|Test 17 1.6I/1.5E rockers||Test 18 COMP XE268H |
|Test 19 Unblown||Test 20 Blown |
|Test 21 Carb||Test 22 EFI 30lb/hr |
|Test 29 Rebuilt |
|Test 31 Unblown||Test 32 Blown||Test 33 Boost |
|Max||424||466||613||697 ||14.7 |
|Test 34 Standard||Test 35 Gapless|
|Test 36 Cam, Manifold |