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so leading on from my previous post, we have now had this ls1 back on the dyno that original motor was tuned on to find out that it is only up about 10hp, basic list of mods from previous tune are 383 stroked with 12:1 comp, cnc ported heads, bigger valves, bigger cam. has nice headers and exhaust which it did previously. and a standard ls1 intake engine builder is saying advance cam, cam and head builder is saying dont advance cam and to see if intake is restricting it. was just wanting a 2nd opinion as to what you would try next as we cant just keep putting it on and off the dyno and everyone is scratching their heads. if you feel this is off topic then please feel free to delete this post. thanks simon
I've seen this a few times now with cammed LS engines. My intial guess would be the cam timing is out. Just saying 'advance' or 'retard' the cam is worthless without first knowing where the cam is currently dialled in. My suggestion would be to get a degree wheel on the engine and find out exactly where the cam centreline is right now. Then you can compare that to the cam card and decide what you need to do from there. We recently had a cammed LS3 on the dyno where the cam timing was out by about 4-5 degrees and the symptoms were almost identical to what you are seeing.
Unfortunately with these engines, swinging the cam on the dyno isn't a 5 minute job.
cam center line is bang on 110 which is to the cams specs. really don't like the idea of trying different timing so trying to rule out everything else first haha
That sounds a little confusing. If all of the rest of the hardware remains the same as the last tune, I would expect a massive improvement from the cam swap - The stock cam on these engines is pathetic to say the least.
I would look at the basics and make sure that the intake (filter/OTR or whatever you are running) and exhaust are free from restrictions. Beyond that it may be beneficial to try moving the cam but this is a lot of work to just try a pull. The factory intake manifold won't be holding you back right now. My old L98 (LS2 with LS3 heads basically) made 370 kW atw N/A with a stock manifold.
yea something is definitely not right, it had a mild cam in it before and has good headers on it with 3 inch strait through exhaust so dont think that is holding it back. intake is just a 100mm alloy tube with new k&n pod filter on the end. the only other concern is it breaths allot but engine builder reckons its from the extra stroke. other people say its not right. who do I believe lol. an ls2 manifold is meant to be a good upgrade over the ls1 intake (75mm) vs I think 90mm id expect this engine to make an easy 370kw
If you think it's breathing heavy then do a leak down test and see what you've got with that