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Bought a G8 from a mom and pop dealer. They know nothing about it. It has a cam(don't know which one) SLP headers and what appears to be stock exhaust the rest of the way. I brought it to the dyno just to make sure it was ok. Tune is locked which sucks but otherwise looks ok, maybe a little low. My concern is the torque nose dive. Would that be caused by a restricted exhaust? Thanks.
I just checked it out. After the headers it's 2.25 then a 3" x-pipe then back to 2.25. I'm guessing that's a horsepower killer. Anything else to look for to see why it peaks early? Thanks gents.
I just checked it out. After the headers it's 2.25 then a 3" x-pipe then back to 2.25. I'm guessing that's a horsepower killer. Anything else to look for to see why it peaks early? Thanks gents.
Dirty filter, old plugs and wires, half plugged fuel filter, etc. If you don’t know the cars maintenance history those are good areas to start
Buddy on tech here also gained like 70 rwhp once by removing plugged cats
I did the maintenance stuff when I bought it. It was my winter beater but I sold my corvette a couple weeks ago so now I'm trying to hone in on this car. Should have known better to buy a modified car. I usually do it myself so I know what's gone into it. Maybe I'll tear into it one of these days to see what cam it has.
I just checked it out. After the headers it's 2.25 then a 3" x-pipe then back to 2.25. I'm guessing that's a horsepower killer. Anything else to look for to see why it peaks early? Thanks gents.
That's not your problem. The stock midpipe with the center muffler cut out and stock axlebacks aren't that restrictive at your power level. Maybe 10HP at most.
Without knowing what cam is in the car, nobody can help you.
thanks for the positive response. I guess it could be the stock cam but like I said, the idle is pretty lopey. Also has DOD delete. If someone went through all that trouble you'd think they put a aftermarket cam in.
Humor doesn't always translate across the Internet I guess.
The curve looks like a stock cam. Maybe stock for something else; but stock behavior nonetheless. Peaks at about a typical RPM for stock, etc.
Exhaust restriction typically creates more of a "wall" look; the flow reaches a point, and stops. The curve just craters rather than tapering off like that one.
As far as second-guessing about what "someone" "would do", especially if that led you to the conclusion that what they did made sense somehow or is the same as what you would do, I gave up assuming that sort of thing about the human race a LONG time ago. People do stuff that makes no sense to me all the time.
You could put a dial indicator on acoupla push rods and get some kind of idea what it is; maybe not down to the part #, but a rough clue, at least.
Been researching a bit. Looks like stock cam g8 graphs don't even look like that. They have more torque than hp. Mine is the same hp and tq. So to speculate, the aftermarket cam that it has must have the timing retarded? Thanks
Any chance they deleted dod but stayed with a vvt cam? That's pretty much how my trucks dyno looked before getting the tuning straightened out
I mean, it's plausible. I guess the only reason I think it has an aftermarket cam is the idle lope sounds pretty close to my corvette that had a BTR stage 4. And also I work with a guy that has a stock g8 and they sound nothing alike.
03-09-2018, 04:34 PM
Need help with dyno critique 
People do stuff that makes no sense to me all the time.