3800 RPM vs MPH

[MIKES3]

I JUST GOT MY 1.8 ROCKERS INSTALLED!!

I am currently shifting out of 1st gear at about 44mph at 5860 RPMs give or take. Does this makes sense? I have 225 / 55 / 17 tire measurements on my car. I have the 2004 GTP which is the 2.93 gearing. If I want to shift at 6000 RPMs out on the 1-2 shift would it be at 55.8 MPH? Does that make sense?

On the 2-3 shift shift what would the safest RPM to shift at? I was thinking around 5750 @ 99.5 mph, but it does not seem right. What do you all think?

Mike

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[SaturdaysGS]

FWIW, My car shifts out of 2nd and into 3rd at what seems like 5900rpm?/99-100 mph?

With 1.8's i'd shift out of 1st at 6000, and second at 5850rpm.

 

[MIKES3]

Originally posted by SaturdaysGS@Mar 13 2006, 02:38 PM
FWIW, My car shifts out of 2nd and into 3rd at what seems like 5900rpm?/99-100 mph?

With 1.8's i'd shift out of 1st at 6000, and second at 5850rpm.

[snapback]118100[/snapback]​

Right, but at what mph?

 

[alexgtp]

changing rockers does not change your RPM's.

Also the stock TACH is about as accurate as a weatherman.

Are you getting your RPM's thru the tach or are you using an autotap/odbII scanner?

Do you have an aftermarket PCM?
Is this PCM programmed to your 2.93 gears?
Have you had your shift points changed?
If you have a DHP I would recommend having charles change the shift point to what you want ..but make sure to keep it in a safe spot. DOnt want any valve float introduced into your set up.

The tires you have should only throw off your speedo/tach about <1%.

 

[MIKES3]

Originally posted by alexgtp@Mar 13 2006, 03:24 PM
changing rockers does not change your RPM's.

Also the stock TACH is about as accurate as a weatherman.

Are you getting your RPM's thru the tach or are you using an autotap/odbII scanner?

Do you have an aftermarket PCM?
Is this PCM programmed to your 2.93 gears?
Have you had your shift points  changed?
If you have a DHP I would recommend having charles change the shift point to what you want ..but make sure to keep it in a safe spot. DOnt want any valve float introduced into your set up.

The tires you have should only throw off your speedo/tach about <1%.

[snapback]118103[/snapback]​

I have a DHP Power Tuner. I use the scanning device on the tuner to monitor everything. Yes my shift point are not stock. I actually had to adjust from the tune that I got from DHP. It was allowing me to shift at 6200 rpms. I didnt want that.

changing rockers does not change your RPM's.

I understand that, but when you install larger ratio rockers that means you can boost up the RPMs and what not correct?

 

[alexgtp]

Negativo.

Rockers allow the car to breathe better (improve airflow) at the higher RPM's. More air in = more power. Thats basically all it does.

By increasing the rmp shift points you are giving the car more chance to produce more power in the upper RPM's

I would recommend a safe shift point try and keep them under 6200. Unless you have higher spring rates/pushrods and better retainers.

 

[Sinister Drag Designs]

Originally posted by MIKES3+Mar 13 2006, 03:57 PM-->

<!--QuoteBegin-alexgtp

@Mar 13 2006, 03:24 PM
changing rockers does not change your RPM's.

Also the stock TACH is about as accurate as a weatherman.

Are you getting your RPM's thru the tach or are you using an autotap/odbII scanner?

Do you have an aftermarket PCM?
Is this PCM programmed to your 2.93 gears?
Have you had your shift points  changed?
If you have a DHP I would recommend having charles change the shift point to what you want ..but make sure to keep it in a safe spot. DOnt want any valve float introduced into your set up.

The tires you have should only throw off your speedo/tach about <1%.

[snapback]118103[/snapback]​

I have a DHP Power Tuner. I use the scanning device on the tuner to monitor everything. Yes my shift point are not stock. I actually had to adjust from the tune that I got from DHP. It was allowing me to shift at 6200 rpms. I didnt want that.

changing rockers does not change your RPM's.

I understand that, but when you install larger ratio rockers that means you can boost up the RPMs and what not correct?

[snapback]118108[/snapback]​

[/b]

no shifting higher has nothing to do with rockers, its your springs that need changing, and there is no power gain from what i hear over 6-grand with rockers, just float after 6100

 

[MIKES3]

Originally posted by alexgtp@Mar 13 2006, 04:12 PM
Negativo.

Rockers allow the car to breathe better (improve airflow) at the higher RPM's. More air in = more power. Thats basically all it does.

By increasing the rmp shift points you are giving the car more chance to produce more power in the upper RPM's

I would recommend a safe shift point try and keep them under 6200. Unless you have higher spring rates/pushrods and better retainers.

[snapback]118110[/snapback]​

I got the ZZP Rockers Installed. I got the 1.8 rockers, 90lb springs, The pushrods that came with the package. valve retainers and I think thats it, so I would assume that I can go to 6000 rpms

 

[alexgtp]

I think you can safely go to 6000.

Best bet would be to get a DYNO.

And see at what RPM's you stop making power in each gear.

No sense going super hi and inducing unnecessary valve float and or damage.

 

[MIKES3]

Screw it. I think I am going to bump it up a 100 rpms. It wont be quite 6000, but I'll pretend. I'll be careful considering my car seems like its still having its own issues

 

[phat_ridegt]

a standard dhp makes the car shift at 6000 anyway doesnt it? for my 00 a 1.0 created a 6000rpm shift from 1-2 and 2-3. i would say you are plenty safe at 6k man.