XR7 Dave
Registered User
This is not a question, but rather an answer. It is often debated/pondered how much HP the stock injectors will support and when you need to upgrade.
Well, this particular car ran out of injectors at about 245rwhp. The car is a 91 AOD and the relevent mods are as follows:
Full catless exhaust system
Ported exhaust manifolds and cleaned up exhaust ports.
S-Port blower with 10% OD
76MM MA meter
Double IC
CAI w/ cone filter.
For reference, the car hits 14psi immediately and will peg the boost gauge by 3500rpm. The 245rwhp figure comes from a Gtech so take that for what it's worth, but based on my experience and how the car runs I'd say it is pretty accurate. Keep in mind this is a very strong running and well tuned 91 SC. Your results will vary.
Now the interesting thing is how the injectors responded. At 4000rpm the car pulls a commanded 11.8 AF ratio but by 4500 it has climbed to 12.5 - still reasonably safe, then by 5000rpm it has climbed to about 13.5 AF which is NOT safe. Also, since we can see that the injectors are running 100% duty cycle at 4000rpm, operation at this rpm or higher for an extended period of time would be very bad for the injectors.
Just thought some people might find this information useful.
Well, this particular car ran out of injectors at about 245rwhp. The car is a 91 AOD and the relevent mods are as follows:
Full catless exhaust system
Ported exhaust manifolds and cleaned up exhaust ports.
S-Port blower with 10% OD
76MM MA meter
Double IC
CAI w/ cone filter.
For reference, the car hits 14psi immediately and will peg the boost gauge by 3500rpm. The 245rwhp figure comes from a Gtech so take that for what it's worth, but based on my experience and how the car runs I'd say it is pretty accurate. Keep in mind this is a very strong running and well tuned 91 SC. Your results will vary.
Now the interesting thing is how the injectors responded. At 4000rpm the car pulls a commanded 11.8 AF ratio but by 4500 it has climbed to 12.5 - still reasonably safe, then by 5000rpm it has climbed to about 13.5 AF which is NOT safe. Also, since we can see that the injectors are running 100% duty cycle at 4000rpm, operation at this rpm or higher for an extended period of time would be very bad for the injectors.
Just thought some people might find this information useful.