The Cal-look Lounge

I've recently completed the engine build for my street / strip car.  When it was set up on the Mustang dyno at Race Shack I was supprised to find that peak power was made at 6134rpm, with peak torque at 5400rpm.

The engine spec is as follows:

2332cc
10.9:1 c/r
CB Ultra wedge port cnc heads (46 x 37.5mm)
CB 5.6" rods
CB 2289 cam (very similar to engle fk87)
51.5mm IDA's
Running on Bio-ethanol.

Peak power was 163BHP @ the wheels, peak torque was 147ft-lbs.  I'm not disappointed with the figures, far from it, they have grossly exceeded my estimates, and after driving the car it feels pretty quick.   ;)

I just assumed (wrongly) that with that cam / head combo, peak power would have been made higher up the rev range, what do you guys think?

The power seems a bit low. I had a very similar combo on my 2387 and it made 30 more HP.
2387cc
12: 1 CR
Wedgeports with 46 x 37
5.7 rods
FK-89
52 mm carbs
Running on E-85

See dyno sheet here:
http://www.thesamba.com/vw/forum/album_page.php?pic_id=282333

Peak power 228 hp at 6950 rpm
Rear wheel horsepower 195.7

My heads were made by JPM before the ultra wedgeports was availible. Take a look at the manifolds as the ones made by CB were far too small even though CB called them match ported.
Mark Herbert ported the manifolds some and when I got them I ported them some more. When JPM got them he added some weld and ported them even more!

Morning Stretch, how's it going!

What weight did the car come in at? I'm still convinced that there needs to be a correction factor applied to the numbers from that dyno! ;) I'd have expected a little closer to 200bhp with that set up.

Anyway - things like the length of the intake manifolds are going to affect where in the rev range the power will be. Have a search for some of Jim Rattos posts - he seems to have tried most combinations and is very knowledgeable when it comes to remembering combinations of what works and what doesn't! :)

Neil

Morning Neil, i'm good thanks you?

Car with me in it weighs 2000lbs.  Car without me in it weighs a LOT less !!   ;)  ::)

You can't really compare dyno figures unless they were all taken on the same dyno, i'm not looking for more power (yet  ;)), but was wondering about where the power was made.

I notice from your graph Roman that peak power was made at 6900rpm, with a slightly wilder cam, so mines looks about right.

Cheers guys.

Peak power rpm definitely seems low for the engine specification.

Slight giveaway might be the relatively narrow gap between peak torque and peak power. On a street engine I'd expect the difference to be much greater than 600rpm!

The fact peak power is at relatively low rpm for the spec and not too far away from peak torque, I'd suspect something restrictive on the intake side (heads, manifolds, carbs??).

Each time I've tested an engine with restrictive intake (usually heads), the power peaks earlier than expected and tends to flatten off for several hundred rpm rather than continue the expected upward climb. How does it look on the printout?

BTW, agree with you re comparing figures from different dynos.... it's generally a waste of time. You can only make direct comparisons when carrying out subsequent tests on the same dyno (assuming it has the same calibration). Lots of other variables too but that's another conversation  ;)

John,

The power curve certainnly wasn't peaky.  The power rose steadily and flattened off, as you suggested.

The heads are out of the box cnc ported c/w cnc ported manifolds (tall).  The carbs are jaycee 51.5mm ida's with 44mm venturi's.

To be honest I'm happy that it makes power lower down, to my way of thinking lower revs = less stress on components.  Also the broader spread of peak power will mean that shift points aren't as critical.  This will be good for bracket racing.  I hope  ;)

That's another clue.... check the gastric band manifolds... big at the top and bottom but what about in between?  ;)

Manifold cross sectional area should taper gradually from carb butterfly down to head flange. Instead you have hour glass impression.

Minimum csa of manifold is determining ultimate flow potential of your entire intake system.
 
Might involve some welding on manifolds to avoid breaking through but peak rpm and bhp will increase, eliminating plateau on power graph (more area under the curve) i.e. car goes faster/quicker

Yep, exactly as I said earlier. Here is a picture of my manifolds just to get an idea what is needed. The welding/porting from CB wasn't enough so I added some more (the uglier weld on the side towards the engine and on the outside towards the valve covers). A LOT was removed in the middle.

What Exhaust are you running?

I think the cnc heads out of the box need some port work , and cutting for more compression ! As i said in anouther thread , the cnc work is good to have less hand work .
udo

Thanks for the info guys.  I'll get the manifolds modified and let you know the results when I get the chance to get the car back on the dyno.

When I say the heads are out of the box, they have had some work, essentially they have been cut for higher compression and have had all the sharpe edges radiused.  I also smoothed the cnc marks out of the inlet and exhaust ports.  So no major work, just a few hours in the garage with a few rolls of emery cloth.   :)

The exhaust is an 1 3/4" turbo thomas stainless merged header & turbo muffler.

I agree, manifold design for Type 1 style (stock) head needs more work. A good design is the Super Flow or comp eliminator IDA manifold. I think the long Skat trak style, if not ported enough, over accelerates the intake charge, and restricts it at high rpm. It may have worked on 1700-1800cc motors "out of the box" but with nearly 600cc of cylinder volume to fill @ 6000+ rpm... they neck down too much and are probably too long.

it just goes to show ya what hand done heads can do for ya VS the macine type. talk to (schwimmer or rayburn)  they will tell ya two perfect exampels of what 94 bore true pump gas (OEM STYEL) street head engines will make on alot lower  8.6 to 8.8 compression and reg 48s  and smaller cams.  ;) JD.

From those dyno sheets. It looks to me like there is a big issue starting aroun 5,000rpm that just makes power nose downward.
I'd be looking at your fuel system and/or jetting combo. Are you getting enough Alky to the motor?
Something is definatly way off.

Here is the dyno sheet from the Steve Hollingsworth 2276 in the Jade Grenade.

  Customer  2276 Cu Cm 4 Str
  Luke                                  82X94 5.325 rods  50/50 rac gas       
  48 IDA 165m 200a 120ia 65i 40 vents   32 timing                             
  42X37.5 heads                         9. cr K8 berg 1.4 rockers             
  1 5/8 ex w 2 1/2 magnaflow muff                                             
                                                                             
  FUEL SG = 0.720  INERTIA FAC = 0.000
  AIR TEMP = 66.0   REL HUMID =  27 BAROMETER = 29.86 SAE CORR = 1.014
  DRIVE RATIO = 1.0  TORQUE ARM IN =  12.6  LOAD CELL MAX =  250
 
     REV  TQ-RAW  TQ-COR     BHP PRESS-1      O2     AT3     AT4     KT1     KT2     KT3     KT4    BSFC     SFC      ET   DELTA   ACCEL     RPM
     Min   Lb-Ft   Lb-Ft    CORR                                                                 #/hp-hr    #/hr     Sec    Time   Rpm/S     Act

    3300   124.9   126.6    79.6     -23    0.12      32      32      68     182     156     205    0.44    34.8   0.217   0.217       0    3304
    3400   127.3   129.0    83.6     -23    0.12      32      32      68     199     191     297    0.44    36.8   0.733   0.516     196    3405
    3500   132.3   134.1    89.5     -23    0.12      32      32      68     176     188     334    0.45    40.6   1.235   0.502     199    3505
    3600   132.6   134.5    92.3     -23    0.12      32      32      68     211     184     286    0.49    45.1   1.721   0.486     204    3604
    3700   134.9   136.7    96.5     -23    0.00      32      32      68     255     220     383    0.50    48.0   2.200   0.479     217    3708
    3800   135.6   137.5    99.6     -23    0.12      32      32      68     279     230     422    0.49    48.8   2.586   0.386     254    3806
    3900   134.6   136.5   101.5     -23    0.00      32      32      68     195     217     461    0.50    50.8   2.862   0.276     370    3908
    4000   133.7   135.6   103.4     -23    0.00      32      32      68     203     200     451    0.51    52.5   3.234   0.372     266    4007
    4100   133.3   135.2   105.8     -23    0.12      32      32      68     271     235     424    0.55    58.5   3.662   0.428     245    4112
    4200   134.2   136.0   110.0     -23    0.00      32      32      68     261     271     447    0.55    60.8   3.856   0.194     691    4246
    4300   134.8   136.7   112.7     -23    0.00      32      32      68     242     272     455    0.54    60.8   3.922   0.066    1273    4330
    4400   136.8   138.7   116.4     -23    0.12      32      32      68     240     246     428    0.52    61.1   3.996   0.074    1068    4409
    4500   137.9   139.8   120.0     -23    0.12      32      32      68     261     239     383    0.52    62.8   4.278   0.282     344    4506
    4600   135.8   137.7   120.7     -23    0.12      32      32      68     246     246     340    0.52    63.1   4.595   0.317     319    4607
    4700   138.9   140.8   126.2     -23    0.00      32      32      68     252     252     349    0.50    62.8   4.797   0.202     490    4706
    4800   146.0   148.0   135.3     -23    0.12      32      32      68     249     224     384    0.46    62.3   5.010   0.213     460    4804
    4900   148.3   150.4   140.5     -23    0.12      32      32      68     241     231     388    0.44    62.0   5.195   0.185     562    4908
    5000   145.3   147.3   140.5     -23    0.00      32      32      68     235     250     488    0.44    62.0   5.347   0.152     651    5007
    5100   140.5   142.4   138.5     -23    0.12      32      32      68     233     221     379    0.46    63.7   5.507   0.160     638    5109
    5200   139.0   140.9   139.7     -23    0.00      32      32      68     196     206     355    0.47    65.7   5.668   0.161     596    5205
    5300   138.8   140.7   142.6     -23    0.12      32      32      68     244     204     337    0.47    67.7   5.805   0.137     861    5323
    5400   138.6   140.5   144.7     -23    0.00      32      32      68     246     192     361    0.48    68.8   5.924   0.119     739    5411
    5500   137.7   139.6   146.5     -23    0.00      32      32      68     257     235     412    0.48    70.5   6.016   0.092    1087    5511
    5600   136.7   138.6   148.1     -23    0.00      32      32      68     242     259     407    0.48    71.7   6.110   0.094    1074    5612
    5700   135.5   137.4   149.8     -23    0.12      32      32      68     215     200     400    0.48    72.2   6.191   0.081    1395    5725
    5800   134.8   136.6   151.1     -23    0.12      32      32      68     207     193     391    0.48    72.0   6.258   0.067    1269    5810
    5900   134.0   135.9   152.9     -23    0.00      32      32      68     215     178     353    0.47    71.4   6.344   0.086    1140    5908
    6000   133.5   135.3   155.0     -23    0.12      32      32      68     219     170     286    0.46    70.5   6.459   0.115     939    6016
    6100   132.8   134.7   156.9     -23    0.00      32      32      68     205     180     358    0.44    68.8   6.554   0.095    1105    6121
    6200   132.1   133.9   158.4     -23    0.12      32      32      68     216     176     439    0.42    67.1   6.618   0.064    1422    6212
    6300   130.4   132.2   158.9     -23    0.12      32      32      68     208     173     343    0.41    65.4   6.717   0.099    1020    6313
    6400   127.6   129.4   157.9     -23    0.00      32      32      67     211     238     356    0.41    64.5   6.842   0.125     792    6412
    6500   123.7   125.4   155.4     -23    0.12      32      32      68     246     252     341    0.42    64.8   6.974   0.132     735    6509
    6600   120.2   121.8   153.2     -23    0.12      32      32      68     245     241     389    0.43    65.1   7.121   0.147     646    6604
    6700   116.8   118.4   151.2     -23    0.12      32      32      67     229     197     331    0.44    66.0   7.281   0.160     650    6708
    6800   112.3   113.9   147.6     -23    0.12      32      32      68     239     205     375    0.47    69.7   7.463   0.182     544    6807
    6900   106.7   108.2   142.2     -23    0.12      32      32      68     226     224     399    0.51    72.0   7.717   0.254     386    6905
    7000   101.3   102.7   136.9     -23    0.12      32      32      68     196     221     343    0.53    72.2   8.024   0.307     322    7004
    7100    96.1    97.4   131.8     -23    0.00      32      32      68     216     189     313    0.55    72.8   8.370   0.346     298    7107
    7200    92.3    93.6   128.4     -23    0.00      32      32      68     215     204     345    0.58    74.5   8.756   0.386     254    7205

Here ya go, Barry!

I should dig up the dyno session from Roger Crawford's in 2000
2276cc street engine, Comp Eliminator 46 x 37 by Heads Up, 10.0:1, s/s valves, Heads Up 320 steel cam (280@ .050), 48IDAs, 40mm vent 165 main, 170 air F11 tube

made 213 @ 7100 and 175ftlb @ 5500.

cheers luke.i,ll make a photocopy of this page for my records.

(http://www.johnmaherracing.co.uk/images/flowbench/cooper_dta.gif)

Results from a 2276cc n/a fuel injected street motor, fitted with Dick Nuss heads (044s, fitted with 45mm x 37.5mm valves).
Porsche cooling, stainless 1 3/4" header and 2 1/2" turbo muffler.
Very driveable on the street - fitted with Berg 5 transmission.
Figures are flywheel bhp in full street trim i.e. muffler and belt fitted.
Dick Nuss heads also allow more peak bhp rpm (superior flow) than seen on the next engine.
Never been on a drag strip.... yet  ;)

===========================================

(http://www.johnmaherracing.co.uk/images/flowbench/noel_2276.gif)

Another 2276cc street engine. Normally aspirated, 48IDAs, 9.5:1, mildly reworked (fluff and buff, good valve job), CNC oval port 044s: 44mm x 37.5mm
Fitted to a real street car i.e. full interior, all steel panels, original glass etc plus roll cage.
12.30 @ 108mph with 3.88 r&p, 1.48 3rd, 1.04 4th.
MT DOT tyres.
These figures are also flywheel bhp, through same style 1 3/4" exhaust and  2.5" muffler as engine above but no fanbelt.

Check how the EFI engine can be pulled as low as 2500rpm at wide open throttle whereas the IDA engine wanted to stall out when pulled much lower than 3500rpm.

Figures have NOT been subject to the 'Add 4 bhp per 1000rpm' bullshit correction factor  ;)