Raising the safe rev limit on a 3.2?

[safe]

Hi
How do I raise it to 7000-7200?
How much do the ARP-bolts do?

[Flat6pac]

Its done on the PROM when you chip the brain. The PROM manufacture is in control of that element.
Bruce

[BURN-BROS]

Originally Posted by safe

How much do the ARP-bolts do?

ARP's are mandatory if you want to spin safely above the stock redline. The stock 9mm bolts are questionable at the stock redline IMHO.

[dentist90]

related question: What max rpm is safe on the 3.2 with stock valves/springs without piston contact (ie, floating the valves)?

[Eagledriver]

With stock valve train I wouldn't go over the stock redline. I've heard that the valves will float at around 6800 with stock springs and a 3.2/SC cam.

-Andy

[safe]

But the Carrera Clubsport has the redline at 6750 with stock rodbolts?
They have a lighter valve train, but that wouldn't affect the rods, right?

The problem is that I had the engine on the dyno for mapping yesterday and it develops peak power ABOVE 6800.... Had to convince the dyno guy, "Don't pull above 6800!!!"

EDIT: It's a street car not a track car that pulls to redline in every shift.

[BURN-BROS]

Originally Posted by safe

But the Carrera Clubsport has the redline at 6750 with stock rodbolts?
They have a lighter valve train, but that wouldn't affect the rods, right?

The problem is that I had the engine on the dyno for mapping yesterday and it develops peak power ABOVE 6800.... Had to convince the dyno guy, "Don't pull above 6800!!!"

EDIT: It's a street car not a track car that pulls to redline in every shift.

Magnus,

I have seen too many dead 3.2 cranks that are out of street cars to recommend anything but stock. Try a different timing setting if you can to bring the power band down. Or install ARP bolts.

[safe]

Originally Posted by BURN-BROS

Magnus,

I have seen too many dead 3.2 cranks that are out of street cars to recommend anything but stock. Try a smaller timing setting if you can to bring the power band down. Or install ARP bolts.

Cam timing? What can I do there to bring down the powerband?

[cgarr]

Doesn't more overlap give you low end grunt? but sacrifice some top end? Its a question

[BURN-BROS]

Originally Posted by safe

Cam timing? What can I do there to bring down the powerband?

Talk with your cam grinder to see what your options are with the grind you have. They should be able to give you what the limits are.

Originally Posted by cgarr

Doesn't more overlap give you low end grunt? but sacrifice some top end? Its a question

More overlap lowers displacement/ dynamic compression. This reduces torque and pushes usable power up the rpm band. Less duration and smaller overlap, like an SC cam produces usable power much lower than an S cam. Study the lobe center, timing specs from Wayne's book to help recognize the relationship. Higher timing specs and smaller lobe centers(more overlap) are for the high rpm applications.

[Eagledriver]

You can advance the cam to give more low end torque. The spec for your car is around 1.2mm at overlap TDC. You could go to 1.5 or 1.6mm and lower the powerband somewhat.

If you are tracking the car all the time I'd replace the rod bolts with ARP. You don't have to split the case to do it if you don't want to.

-Andy

[safe]

OK, I might try to advance the cam, but I think that will be a job for the next winter
Will advancing it bring the valves closer or further away from the pistons (euro 10.3:1 compression, stock cam)?

If I open her up for arp rod bolts and stiffer valve springs, is 7000+ safe?

Made my first you tube video
http://www.youtube.com/watch?v=mDjeGvaK0gs

I'm always annoyed how puny the sound gets through a camera.

[safe]

Dyno sheet fo the pull.

[911st]

What do you know about your motor, cam, exhaust, chip?

Stock 3.2's make peak HP at 6200. There has to be some reason yours dose not do the same. For comparison, go to 911chips.com and look at there dyno stuff.

Did you check your Air Fuel Ratios with your dyno pull.

Euro pistons by them selves would not do this. Cam timing might.

It seems that somthing is not right.

[safe]

Originally Posted by 911st

What do you know about your motor, cam, exhaust, chip?

Stock 3.2's make peak HP at 6200. There has to be some reason yours dose not do the same. For comparison, go to 911chips.com and look at there dyno stuff.

Did you check your Air Fuel Ratios with your dyno pull.

Euro pistons by them selves would not do this. Cam timing might.

It seems that somthing is not right.

Stock internal, OBX headers, 48mm ITBs, Emerald EFI.
AFR around 13:1 up to 5000 rpm then gradually lower to 11.5:1 at 6800.

[304065]

Hmm the curves cross around 3500 rpm, is that because the test was done in IV?

Cool video Magnus! What is the dyno procedure, full throttle in IV and then clutch in at the redline?

[safe]

Originally Posted by john_cramer

Hmm the curves cross around 3500 rpm, is that because the test was done in IV?

Cool video Magnus! What is the dyno procedure, full throttle in IV and then clutch in at the redline?

Thanks, John!

Not sure why the curves cross at 3500, or if that is good or bad?
4th is top gear in my car. Yes, full throttle and clutch at readline.


The muffler is a stock -74 Bischof 2 in 1 out. I wonder if I have more power to gain by a better muffler?

[911st]

Individual Throttle Bodies!

OK, this is not a mostly stock 3.2. Yes, you need rod bolts.

Yes, the stock 2/1 muffler is costing you HP.

I suspect the TQ and HP do not cross at 5252rpm because there are different scales on each side of the graph.

[safe]

Originally Posted by 911st

Individual Throttle Bodies!

OK, this is not a mostly stock 3.2. Yes, you need rod bolts.

Yes, the stock 2/1 muffler is costing you HP.

Not sure if the rod bolts are worth if if they don't make a significant increase in rpm-capability. It's a 20000 miles engine, so its very leak free and nice.

With all the work to change rod bolts, why not put in a set of new Carrillo-rods or equivalent? I'd like to be able to take it to 7500 and make good use of s
-cams in the future.


Unfortunately I have to comply to a 95db noise regulations, so many muffler choices are closed.

[911st]

Also not your typical Foot Pounds to HP graph. It is a euro thing.

6800 is believed to be the safe limit w stock rod bolts. Some have gotten away with higher, some not.

If stock euro pistons, you can not run S cams with them with out having valve reliefs cut into them for clearance.

To spin a 3.2 long stroke motor to 7500rpm safely I believe you have to use race valve springs and cross drill the crank and make mods so it gets oil not just from both ends but from the middle.

Yes, Carrillo rods are a good upgrade for a 3.2 or 3.3 that is going to spin past 7k.

The best.