[Jetflo]

With the intake opened up, it's clear there's still lots of power left past 5800rpm and that hitting the next shift after 4000 rpms is a good goal. I've been pouring over the data logs and can't get around the potential advantages of running past 6000 rpm before shifting from at least 1st gear. It would help with second as well.

Can the engine survive?

It seems like the 6050 rpm redline I've been running for the last few months is clearly no problem for it. However, I read something about the 3.8L crankshaft being unstable past 5500 rpm. I've also read on this forum that no one has broken a 3.8L crank.

Has anyone galled the main bearings from excessive rpm?

I've set my redline to 6250 with 6100 rpm as my target for shifting and I'm headed out to give this a try. Am I nuts?

Thanks!

[SlowSix]

Yep. If you look at a dynograph these cars stop making power around 5300ish

[Jetflo]

Originally Posted by 01SilverSixer Yep. If you look at a dynograph these cars stop making power around 5300ish

True!

However, this car has:
Windstar
ported/half shafted throttle body
4" piping with filter in fender
JBA headers
pypes x pipe
magnaflow catback
tuned by Jetflo using SCT Advantage III
* fuel pressure increased to 53 psig
* MAF transfer function revised for intake setup
* fuel timing advanced 8 degress
* manifold volume reduced to 4.625L
* fuel table revised to maintain 12.9-13.1 AFR @ WOT from 2K to 6K rpm
* IMRC switch point reduced to 3220 rpm

It doesn't sound or feel anything like a stock 3.8L. This is also a manual transmission car with 3.73 gears. Hence, in this case exploring higher rpm operation is justified.

The question is: Will the engine hold up?

[SlowSix]

Even with all that you're still not gonna be seeing much power above 5300.
The engine should hold up but I wouldn't be banging the car off the rev limiter all day long.

[walt1120]

i shift at 6500rpm 1st gear and 6200-6300 2nd gear.

Been running it like this for months on stock bottom end and i probably do at least 1 WOT run a day

If anything youd probably have to worry about the stock valvetrain before the bottom end.


Oh and you have a stock cam, your power is probably dropping off at about 5500. I think you should do a dyno pull to see if its even worth shifting past 6k.

For some proof...http://www.moddedmustangs.com/forums...peedo-lol.html (note that my speedo isnt calibrated in this vid. the run actually ends at 87mph)

[ESG-642T]

Already been said, not going to be making any power much past the stock limiter.

Curious: why the huge fuel pressure increase?

[Jetflo]

Originally Posted by ESG-642T Already been said, not going to be making any power much past the stock limiter. Curious: why the huge fuel pressure increase?

It was needed to get the fuel table targets to exactly match measured AFR. Adjustments to the MAF table alone would not work past 820 MAF counts, where the engine went lean. My car used to peak around that MAF count level stock. Now it runs from 4500 rpm up with MAF over 820. Peak is about 900 which occurs around 5900 rpm, test after test. The rev limiter was too close at 6000 rpms. I kept hitting it while the engine was sill pulling.

I'm not disputing what is known about the stock 3.8L. I'm suggesting that getting into 2nd and 3rd at more than 4K rpm is worth it. It isn't about peak HP it is about power at 3K rpm vs 6K rpm.

Take a look at the average dyno sheet on a 3.8. The horsepower is not peaky. It's relatively flat. Looking at the curve, you can see that the engine really doesn't make much HP until later in the 3Ks. Past the horsepower peak is not a cliff, it is a gentle downslope. Somewhere here lies the ideal shift point. Where you end up on the other side matters as much as the power you get before you shift.

I've already tried 6250 rpm out and the engine feels very strong past 6K rpm staying right dead on the money at 13:1 AFR. I like it, though data logging shows I never hit the limiter and tended to shift at the target 6100 rpm. It is good to hear that the bottom end will hold up.

Sweet!

[ESG-642T]

You should find a local dyno day and see what it looks like.

[Jetflo]

Originally Posted by walt1120 i shift at 6500rpm 1st gear and 6200-6300 2nd gear. Been running it like this for months on stock bottom end and i probably do at least 1 WOT run a day If anything youd probably have to worry about the stock valvetrain before the bottom end. Oh and you have a stock cam, your power is probably dropping off at about 5500. I think you should do a dyno pull to see if its even worth shifting past 6k. For some proof...http://www.moddedmustangs.com/forums...peedo-lol.html (note that my speedo isnt calibrated in this vid. the run actually ends at 87mph)

I'm not able to view the video. It is encouraging that you are already running a higher rev limit then I was considering.

Thanks!

[Jetflo]

Originally Posted by ESG-642T You should find a local dyno day and see what it looks like.

I have not heard much in my area. I am curious, though I don't expect to see anything outrageous in terms of peak power. I wanted to see how efforts to tune for stable AFR from idle to redline at WOT have paid off. You don't get to spend much time at 5250 rpm in real world driving.

I'd guess 190ish at the wheels at 5800 rpm. I'd further guess still above 160hp at 6100 rpm.

Anybody heard of a San Jose/Oakland/San Fran bay area dyno day soon??

[walt1120]

i understand your argument that it would be better to stay in gear a little longer then shift early and have no power.

Yes youll make more power at 6k rpms in 3rd then you will at 3.5k rpm in 4th.

You do have a 5 speed though, your rpms dont drop as much as it does with the auto. Even shifting at 6.5k my rpms still drop to almost 4k.

Youll probably only benefit from shifting higher in only 1st or 2nd though. For example maybe on the 1-2 shift 6.2k, 2-3 6k and then all others at maybe 5.8k.

Remember that torque is also a factor here. Torque drops off big time on these motors with the stock cam profile. Look at this graph to see what i mean...http://www.v6power.net/dyno/ken_savell.jpg

[Jetflo]

Originally Posted by walt1120 Youll probably only benefit from shifting higher in only 1st or 2nd though. For example maybe on the 1-2 shift 6.2k, 2-3 6k and then all others at maybe 5.8k. Remember that torque is also a factor here. Torque drops off big time on these motors with the stock cam profile. Look at this graph to see what i mean...http://www.v6power.net/dyno/ken_savell.jpg

Agreed. I so wish California was more tolerant of cam upgrades. I'm interested in doing the best possible with a stock cam. Do you think valve springs or roller rockers might benefit with a stock cam?? I can't guess not enough information to predict if it's good HP/$ and it's expensive to test.

I don't really need to shift into 4th at any particular rpm. 3rd gear breaks the speed limit long before redline. It's all about 0 to 60 mph for me.

[ESG-642T]

Originally Posted by Jetflo Agreed. I so wish California was more tolerant of cam upgrades. I'm interested in doing the best possible with a stock cam. Do you think valve springs or roller rockers might benefit with a stock cam?? I can't guess not enough information to predict if it's good HP/$ and it's expensive to test. I don't really need to shift into 4th at any particular rpm. 3rd gear breaks the speed limit long before redline. It's all about 0 to 60 mph for me.

0-60, do the supercoupe swap

[walt1120]

Originally Posted by Jetflo Agreed. I so wish California was more tolerant of cam upgrades. I'm interested in doing the best possible with a stock cam. Do you think valve springs or roller rockers might benefit with a stock cam?? I can't guess not enough information to predict if it's good HP/$ and it's expensive to test. I don't really need to shift into 4th at any particular rpm. 3rd gear breaks the speed limit long before redline. It's all about 0 to 60 mph for me.

You might be able to get away with a small cam. and the weakness in the stock valve train is the valve springs. Ive heard that at higher rpm with the stock springs there is some valve float, but im not 100% sure on that so you might wanna research that. Its all about cost benefit anylisis though...Adding some ls6 valve springs and 4.6 GT spring retainers may prevent any valve float at high rpm but is it really worth it if your going to keep the stock cam?, not imo.

If your really desperate you could put the stock cam from a 4.2L in. Its a little more aggressive than the stock 3.8 cam. ive heard you get about 10hp/10tq from it and a little bit better power band. However it would probably only be worth it if you can get one for very cheap and install it yourself.

The one thing you got going for you is that you can tune your car yourself so that saves alot of time and money no matter what you do.

[ESG-642T]

Originally Posted by walt1120 You might be able to get away with a small cam. and the weakness in the stock valve train is the valve springs. Ive heard that at higher rpm with the stock springs there is some valve float, but im not 100% sure on that so you might wanna research that. Its all about cost benefit anylisis though...Adding some ls6 valve springs and 4.6 GT spring retainers may prevent any valve float at high rpm but is it really worth it if your going to keep the stock cam?, not imo. If your really desperate you could put the stock cam from a 4.2L in. Its a little more aggressive than the stock 3.8 cam. ive heard you get about 10hp/10tq from it and a little bit better power band. However it would probably only be worth it if you can get one for very cheap and install it yourself. The one thing you got going for you is that you can tune your car yourself so that saves alot of time and money no matter what you do.

It saves more money , not time.

[Loki]

I've been wanting to learn how to tune myself. It seems like a fun thing to do on days off, although time consuming.. Where did you guys pick up the knowledge?

[Jetflo]

Originally Posted by Loki I've been wanting to learn how to tune myself. It seems like a fun thing to do on days off, although time consuming.. Where did you guys pick up the knowledge?

I got an instructional video from La Sorta tuning. Probably could find it with a Google search. It doesn't get very deep, but it does cover MAF transfer function tuning, axle ratio, and some fuel table tweaks. They are working on a supercharged V8 in the video so you have to accept it as education rather than training.

ESG is correct. It is extremely time consuming - at least for me.

[Jetflo]

Originally Posted by ESG-642T 0-60, do the supercoupe swap

If I lived anywhere else, the car would already be twin turbo

[mustangmike!]

hmm

Ill tell you something Ive learned.
In this makes the most sense in an auto, depending on the manual driver's skill.

Say 2nd gear makes peak power @ 4500 rpm.

You shift 1st gear @ 5200 rpm and it hits 2nd at 3500rpm. Now you've got to build 1000rpm before you making peak power.

If you shifted @ 6000rpm and hit 2nd at 4300rpm, your 200rpm away from peak power.

This making it have less delay after shift before your making the most of your rpm power band.

Now their is a point at which, you are shifting at too high of rpm, and losing to much power before shift. Their is a balance you must find in that.


Now it kinda makes sense, and I dont remember who/where I heard this from, but it was on this forum.

Your current mods help hp/tq but your cam/valvetrain is the weak point.

Have you considered a "sleeper" cam for more power and not alot of sound so its less obvious ? I haven't paid alot of attention to the cali rules on that shit idk how you'd get away with it.

You could try my 4.2 cam I have lying around too :p

[mustangmike!]

hmm

Ill tell you something Ive learned.
In this makes the most sense in an auto, depending on the manual driver's skill.

Say 2nd gear makes peak power @ 4500 rpm.

You shift 1st gear @ 5200 rpm and it hits 2nd at 3500rpm. Now you've got to build 1000rpm before you making peak power.

If you shifted @ 6000rpm and hit 2nd at 4300rpm, your 200rpm away from peak power.

This making it have less delay after shift before your making the most of your rpm power band.

Now their is a point at which, you are shifting at too high of rpm, and losing to much power before shift. Their is a balance you must find in that.


Now it kinda makes sense, and I dont remember who/where I heard this from, but it was on this forum.

Your current mods help hp/tq but your cam/valvetrain is the weak point.

Have you considered a "sleeper" cam for more power and not alot of sound so its less obvious ? I haven't paid alot of attention to the cali rules on that shit idk how you'd get away with it.

You could try my 4.2 cam I have lying around too :p








And on him shifting at 6500rpm, that is not a stock cam, so you can really compare.