Anyone Out there with a stroker 4.1? I was on a chasis dyno to tune my reciently built motor.I noticed that the motor only pulled to 5,600 rpms then the graph would drop off, you can here the motor struggle at high rpm?Iam runnig 25psi and have adjusted air fuel ratio richer to lean and no diff. My stock 3.8 allways made it to 6,000 easy.Something iam missing?
Max Rpm Stroker Motor
- Thread starter seeya v6
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Big Turbo Scott
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What is your installed height? Seat and open pressures? Are you using a locator? What ratio of rocker?
You might want to list the whole build with mods..
- Joined
- May 26, 2001
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Having done a few 4.1 strokers, these numbers are normal for your build.
If this is supposed to be a race engine which needs to RPM over 7000, you need to change a few things including the cam. My current 4.1 will run 10.0 with 17 psi of boost.
What was your HP?
Thanks for the help. My spring press is 140 closed and 300 open. The installed hight is 1.700 across the board,I have 1.65 rockers and 534 estimated lift with my 212-212 cam.I made 560 rwhp at 25psi on pump gas and meth.Iam tryin to make power to atleast 6,000 and 600rwhp?
I would agree you need to do some work in the valve spring/cam area. As far as the stroker issue, you should be able to spin it up as much as your valvetrain will allow (within reason I mean). I've hit 8100 before and shift regularly at 7600. We have found the engines make big power even when run on the rich side with low timing when you have the combination right.
why did you switch from the 218-212 cam?
The first time I had my stroker motor built I had a piston break and spun a rod bearing,and damaged a lobe with only a few hundred miles on it.The 218-212 cam had the same max rpm of 5,600,I freshened the motor and used the 212-212 because I have used it before on stock 3.8 and was very happy with it.
Should I have gone with a 224-224?
Should I have gone with a 224-224?
Going to the other extreme of small cubes and a large cam using stage I style heads that do not have impressive flow bench numbers, my engine starts to lightly lay down at 7,300 rpm.
Given a restrictive head (not a stage II head), as you increase stroke (cubes) intake port flow velocity is moved closer to a choke point. If you're going to stick with that head you will have to help it out with more creative camshaft specs if the goal is more power higher up in the rpm band.
Given a restrictive head (not a stage II head), as you increase stroke (cubes) intake port flow velocity is moved closer to a choke point. If you're going to stick with that head you will have to help it out with more creative camshaft specs if the goal is more power higher up in the rpm band.
