Low down on the truck is this... 1992 Dodge Dakota. 408 stroker, meaning its a 360ci block with a 4" crank and .030 over.

Rear mount TC76 turbo
Edelbrock aluminum magnum heads
9.3:1 compression
tremec TKO600, 3.91 rear gears and 29" tires

Made 537RWHP on 10# at 4750RPMs and 606 RWTQ at 4500.

My goal was hit, I wanted 525RWHP.

All controlled by a FAST XFI unit.


Heres my ? though.... Ive built everything on this truck myself except for the motor.... I left that up to someone else, we'll call him Bob.
Bob picked up a cam from hughesengines.com

Here are the specs
Camshaft Technical Details
Intake Valve Lift 1.5
Exhaust Valve Lift 1.5 .510"
.510"

Intake Valve Lift 1.6
Exhaust Valve Lift 1.6 .544"
.544"

Intake Duration at .050" 218°
Exhaust Duration at .050 228°

Lobe Separation Angle 114

Intake Opening at .050" -2° BTC
Exhaust Opening at .050" 51° BBC

Intake Closing at .050" 40° ABC
Exhaust Closing at .050" -3° ATC

Min. Suggested Cylinder PSI 165

Sweet Spot RPM 2500 - 6400



Its got a little bit of lope to it that the wife and I both like, it gets attention cause the truck looks stock otherwise. BUT, Ive been reading of smaller motors making the same HP at almost the same RPM on the same boost.... Thats not what REALLY bothers me though, I dont think that there is any way in hell Im ever going to make the tail pipe emissions test in MD with this cam. It likes to be no leaner than 13.0-13.3 on areas close to decel, or like in the area that I know Im going to fail on which is where you hold it at 2500RPM for several seconds. It seems it just likes to be rich all over, or else it starts to miss etc.... Kinda seems like it should make a little more TQ down low in the RPMs too tough w/o boost.... Running 28* timing at idle, got the best vac (~18") at 13.0AFR, about 30* at 0KPA, and 22* at 10PSI.... 35* down low in the KPA from 1300RPM up I think.

Called Cammotion, just for shits n giggles, and they suggested a 220/214 cam, not sure of the LSA though but I would think somewhere around 114-115? Do you think that would be a better match? Id hate to loose the lope, but for better all over power and better driveability, I think Id swap this winter.

The truck

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that cam looks more suited to blower really with 10* exhaust duration more than the intake and a huge bias in exhaust lift too.....but then again, i've seen turbos make stupid power with "weird" cams.

 

With the exhaust not open as long, I'd think it would be better for emissions. Since the intake is open longer, it would probably make around the same power and might even spool faster given less exhaust opening. You do have no valve overlap already, -5 degrees to be exact, so how much better for emissions doesn't seem like it'd be too much in my eye.

 

I think you read it wrong. Its showing both intake and exhaust on a 1.5 rocker and then on a 1.6 rocker. Its got the same lift on intake and exhaust.

 

you're right jaredsamurai, i did read it wrong.

 

So aside from the duration, what makes the "reverse pattern" cams like the 220/214 so different then? Is it where the opening and closing events are?

 

basicly where the exhaust valve opens , and intake valve closes... thats all that matters.....period
that large stroke , will give heaps of torque... pull like a 16 yr old...

 

the reverse split might work better if the turbo was not remote mount, but i think because it is you may actually hurt your spool up becuase your already disadvantaged by loosing all of the exhaust energy before it gets to the turbo so i dont think the cam would help. the miss almost sounds ignition related to me, and the adding of fuel is just hiding the problem, maybe at the miss try retarding a little more and take some fuel out then. or what heat range are the plugs and what gap

 

Exhaust lobe looks good. The intake lobe is way too damn small for a 400 inch motor. If it were mine I would look at a single pattern 228/228 On a 113 lsa with a 109 icl. I don't think it'll help emissions but I do think it'll help make some more power. As far as your missing torque goes have you tried putting some more timing in it? What AFR are you running at 10 psi? 22 degrees seems kinda conservative. I'm usually at 24 or 26 at that point but I also only pull 6 degrees for 10 psi. If you wait till 4 or 5 psi to start pulling timing it will help with spool and midrange torque.

 

Actually I was only shooting for 525RW, I ran out of $$ for the billet main caps and that TKO600 is rated of course for only 600TQ coming into it... With 606 on the ground, kinda pushing my luck as it is, what do you think? Magnum blocks arent known for there outstanding strength anyways, 600HP seems to be the limit if you want to get any miles out of it. At 96kpa which is round about what I see here all the time at startup, I think Im at 30*, at 104KPA I think Im at 26 or 28 and drop quick from there... that really helped a lot with spool when I changed that after doing some reading on here, this site has been a big help... Bob, also did the WOT tuning... Not sure if he wasnt interested that day in the DD stuff, or didnt know much about XFI, I had the computer in my lap the whole time, so Ive made a good number of changes, but left the 22* alone. It made the power I wanted at that *, so Im not really needing to push it ya know?

IAT temps on short 1/4 mile length street pulls are most of the time 60* (or less) over ambient my the end... No room for an A-A, and cant fit a biger A-W, not interested in meth. But I dont think its all that bad really.

With a 525RWHP goal, would you still suggest the same cam? Here is the graph, spool was slow then, it was b4 I changed the spark map.

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i would just add too that you do not need more intake duration if your only revving to 5200 anyway

 

So thinking about this now, probably wrong, but.... Keeping the intake lobe the same, what about opening that exhaust valve a little later then, cutting down on the duration at that point and maybe letting that 4" crank do a little bit more work?

Typically speaking, at what crank angle has most of the work been done, and is ideal to open the exhaust valve then on a turbo stroker?

 

if youre just worried about emmisions what about cutting out a section of the exhaust and put a couple of v bands in there so you can easily sawp in a set of cats for testing the eaisly exchane those for a section of straite pipe after you pass? if the v bands are to much money band clamps would prob work pretty well also.

 

His truck is already setup to swap a cat in on V bands...

From what I'm told cats work best at 14.7 AFR which may be a problem since his truck likes to idle around 13...

 

blak to answer your question about the crank, the most amount of work is done when the leverage is highest which would be halfway through each stroke, with leverage increasing to that point then decreasing away from that point. i still think ignition is the issue, replace plugs check wire and cap and rotor, i had a miss around 2500 light load when my cap button wore out and wasnt contacting rotor. also with your exhaust duration question, it is possible that even with no overlap on your cam you could be having intake charge contamination when the intake valve open because your piston hasnt moved very far after the exhaust closed so whatever burnt charge is still in the combustion chamber is probably still at a higher pressure that that of the intake pressure. this would be more prevalent if you have very high exhaust back pressure then the cylinder will have an equal pressure even after the exhaust valve has closed, and again the piston hasnt moved far enough down the stroke to lower that pressure. a possible fix for this which i have seen work well is to retard the entire cam a few degrees, which will delay the intake valve opening until the piston has moved further down its stroke. sorry i ramble a lot.