Question for engine pro users...

[EspanolaGuitarista]

... what is your highest torque/ horsepower output for a 3400. I tuned mine yesterday at 336 ft-lbs @ 4600 and 322 horsepower at 5900. Did I screw up somewhere. Camshaft 219/219 .550/.525 LSA 112. Split plenum design. Headers 30 inches. 1.625 primaries.

[Ducatiman]

WOW thats pretty damn good how did u tune the computer or did you use a haltech ecm

[sil]

hes using a simmulation program, sorta like desktop dyno

[SappySE107]

Im using dynomation. Im not sure what all engine pro has for inputs or id give you what I have.

[SappySE107]

I assume its NA you are talking about. Do you have the .006 and .050 specs for the cam? Hell, do you have a stock 3400 setup? Id like to know what your program gets for using the same specs as dynomation.

[EspanolaGuitarista]

I am not sure...

...on all the specs. The specs for average port diameter are probably off. I used 1.4 for exhaust and for intake. 1.65 diameter for the intake port opening. 1.5 for the opening for the exhaust. That seems to work the best. The camshaft is on a .050 spec. I went up to 242/238 on a 110. Something like 375 ft-lbs and 383 horspower at 6900-7000 rpm with a 120% V.E. That would be streetable with more LSA. Why does peak V.E. happen at 5200-5600? I can only run about 10 degrees of advance in that range. 16 deg. at the top end. I run about 8-10 degrees on average. I am using thermal coating. A tight squish, fast burn chamber. My plenum is 30% engine displacement with a 65mm throttle body, but running two 52mm seems to help with the huge cam. 1200 cfm total since EFI sees way more CFM than carbs. My intake runners are 6.6 inches with 4 inches for port length. 1.625 diameter runners and 1.5 primaries. What are the crankshaft mains width. I inputed .75 inch as a guess. I'll post my data sheet. I forgot to bring my memory stick with me. I decided to go with a 219/219 just for streetability reasons. My exhaust outflows my intake but the engine seems to like it. I don't seem to have much reversion or short circuit at idle. I am running 11.5:1 compression with all the setups. They seems to need more cylinder pressure.

[SappySE107]

So your program uses plenum volume and spark advance? It uses average port diameter? Id like to see the data sheet when you get a chance

[EspanolaGuitarista]

Question for Sappy...

...Would you happen to have the runners volumes of either the intake or exhaust manifolds? That would be in cc's. I've got the stock engine running 202 torque @ 4200, 186 hp @ 5200. I think that is close enough. With the 65 mm throttle body there is 3 more ft-lbs of torque, 1 ft-lb higher average and 6 more horsepower. Headers make a very big difference. At 33 inches the motor picks up huge on averages and peaks.

[SappySE107]

It would be pretty hard to CC the runners in the plenum without cutting one up. I don't have any cc numbers. Dynomation uses dimensions and lengths, not volume. I wish I had a program that used both, and could map out the ports in cad or something. Probably 100k software to do that.

Did you get my cc numbers for the ports? Im curious but what does your program say if you use the stock flow numbers but give it about 15cc less volume.

I think your numbers are pretty close to what I get though for the 65mm TB.

[bszopi]

It might take a little work, but I am pretty sure I can draw the runners (at least for the plenum) in CAD and get a volume (in in^3, which could easily be converted to cc's). The lower manifold ports would be alot harder to draw, but could be more easily cc'd with a burrette.

[EspanolaGuitarista]

Yeah, cc' ing is definately better, highly accurate. What I need to know is the length of the runners from the intake port to the plenum. I have 6.5 inches. The 1 inch phenolic spacer with heat passage blocked off makes good power but at 7.5 inches the runners are out of tune. Basically you gain peak torque(+3) and lose peak horsepower(-4), but gain about 8 overall because of heat. 0.25 spacers would be cool. Stock heads seem to be worth 300 horsepower @ 6600. Camshaft 252/252 .630/.525 @ .050.

[SappySE107]

15.75" is the runner length on the intake, measured from the valve seat to the runner opening inside the plenum.

[EspanolaGuitarista]

Thanks....

....Where is cc information? 15.75. So I have 4 inches for the port so. 11.75 for the intake. Damn, I'm way off! How did I get so close on the numbers then. I have 6.5 for the runners. Which works very well for the 252 cam by the way. I have stuff I need to learn.

[SappySE107]

I have 114.4 cc for the stock 3500 intake port and 68.6 cc for the stock 3500 exhaustport . I have 111.6 cc for the stock 3400 intake port and 70 cc for the stock 3400 exhaust port. Are these close to what you are using?

Do you need the lower intake still? I dunno how I can go about doing plenums for individual runners. Also, can you take a stab at something for me. I want to know what the performance does if you take the stock 3500 flow numbers (i will be posting those numbers on the site as soon as I flow the 3 cylinders on a stock head) with the stock cc, and then decrease the cc measurement but leave the flow the same. Id like to know what happpens overall as well as what cc is min for getting gains before losing top end too much.

[EspanolaGuitarista]

Thanks for those numbers...

....I haven't been running any cc numbers into the sim. I have been running your flow numbers like suggested from the program:

.05
.1
.15
.2
.25
.3
.4
.5

Getting the low valve lift flow is crucial since this is where the shrouding occurs at for the most part. Also, are you using a pipe on both sides when you flow the heads? Having the port cc's will be extremely helpful. If you can get the port flow numbers for the 3500 heads, intake and exhaust manifolds and vloume cc's for all plus plenum volumes that would make mapping out these new ports much more accurate and possible guide us in a direction to more power and camshaft design. Do you want to posts the flow numbers? I would use it as part of design development for your business. I have nothing better to do than be a research engineer.