What does the difference between 225 and 375 hp feel like?

[Blownrunner]

What does the difference between 225 and 375 hp feel like? My 91' seems really quick in valet mode, but i do not think that with the secondaries on I am getting the additional 150 hp, although it is faster (acceleration test). With secondaries on, I can spin the tires at about 5k rpm in 1st gear.

Thanks everyone. Maybe I should invest in a fuel pressure tester...

[Kevin]

I don't know if i've ever really driven the car in normal mode. judging by the way it feels when the secondaries don't open, I'm going to say it's a vast difference

[efnfast]

If it falls flat after 5k rpm, the secondaries are not opening. With the secondaries, the tach should fly to 7 grand

[We Gone]

Lots of guides here on how to check it out. I can tell just by the sound not to mention the much better pull when the key is on. As others said after 5k it goes flat with the key off.

[Dynomite]

Lots of guides here on how to check it out. I can tell just by the sound not to mention the much better pull when the key is on. As others said after 5k it goes flat with the key off.

See Secondary Functional Test and Reconditioning the Secondary Actuators (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-4.html#post1581665189)

With Key On........
Find the Pink Wire which is C17 (or pink wire with black strip) on the ECM. Insert a Paperclip along side the Pink wire
and attach a ground wire with Alligator Clip on both ends. Pin C17 is located in the Green Connector
second connector on the ECM from the passenger side.
http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite7/007bd685-3861-4028-99e6-e6d8764dce7e.jpg
Look down on the Passenger Side in the ...........................Look down on the Drivers Side in the
direction of the screw driver (Use a Flashlight). ..............direction of the screw driver (Use a Flashlight).
You will see the shaft of the canister which will ...............You will see the shaft of the canister which will
move toward the FRONT of the engine when ...................move toward the REAR of the engine when
you ground the Alligator Clip (The Front of the ................you ground the Alligator Clip (The Rear of the
engine is to the Right in the Photo)..................................(engine is to the Right in the Photo).
http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite7/c4108afa-77a3-42a0-bbef-481fe4ee3dab.jpghttp://i287.photobucket.com/albums/ll142/dynomite007/Dynomite7/8d5415aa-de81-4ffc-bfbc-f9e90a8d82fd.jpg

[efnfast]

Hey Dynomite, nice throttle cable clip

[Dynomite]

Hey Dynomite, nice throttle cable clip

Carter Bling....then I rethread the bracket hole and use the SS Allen Head bolts that fit the TB Coolant Cover Throttle Body Coolant Cover SS Bolts (http://www.jerrysgaskets.com/bolt-set-t-body-coolant-cover-stainless-steel-90-95-2e4)

[efnfast]

Can't beat the Carter bling.

[KILLSHOTS]

What does the difference between 225 and 375 hp feel like? My 91' seems really quick in valet mode, but i do not think that with the secondaries on I am getting the additional 150 hp, although it is faster (acceleration test). With secondaries on, I can spin the tires at about 5k rpm in 1st gear.

Thanks everyone. Maybe I should invest in a fuel pressure tester...
Are you asking whether your secondaries are functional? If so, just go for a ride. With your foot to the floor, you CANNOT rev past about 5100-5200 rpm if they aren't functional. That's the easiest way.

Well, maybe checking whether the FULL ENGINE POWER light is illuminated is a little easier, but not much.

[Blownrunner]

Are you asking whether your secondaries are functional? If so, just go for a ride. With your foot to the floor, you CANNOT rev past about 5100-5200 rpm if they aren't functional. That's the easiest way.

Well, maybe checking whether the FULL ENGINE POWER light is illuminated is a little easier, but not much.

Really? Did not know that, I will have to try that out sometime in normal mode. Thanks.

[Blownrunner]

See Secondary Functional Test and Reconditioning the Secondary Actuators (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-4.html#post1581665189)

With Key On........
Find the Pink Wire which is C17 (or pink wire with black strip) on the ECM. Insert a Paperclip along side the Pink wire
and attach a ground wire with Alligator Clip on both ends. Pin C17 is located in the Green Connector
second connector on the ECM from the passenger side.
http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite7/007bd685-3861-4028-99e6-e6d8764dce7e.jpg
Look down on the Passenger Side in the ...........................Look down on the Drivers Side in the
direction of the screw driver (Use a Flashlight). ..............direction of the screw driver (Use a Flashlight).
You will see the shaft of the canister which will ...............You will see the shaft of the canister which will
move toward the FRONT of the engine when ...................move toward the REAR of the engine when
you ground the Alligator Clip (The Front of the ................you ground the Alligator Clip (The Rear of the
engine is to the Right in the Photo)..................................(engine is to the Right in the Photo).
http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite7/c4108afa-77a3-42a0-bbef-481fe4ee3dab.jpghttp://i287.photobucket.com/albums/ll142/dynomite007/Dynomite7/8d5415aa-de81-4ffc-bfbc-f9e90a8d82fd.jpg

Yes, thanks for this info. I have been able to verify this using my Snap-On MT2500 scanner also. I can turn the secondaries on, although I have not tried it with the engine running. It will also turn on the fans. I guess it turns on everything the ECM controls for troubleshooting.

I have thought about it and although both fuel pumps work, thinking they can have degraded performance, maybe age or from ethanol. I think back to my injectors. Already had low voltage to the pumps from a bad relay. And two new pumps will only cost about $180. When some people sell their cars, they advertise that it has new fuel pumps, so I will see. Thanks.