I have a 1990 Vette with mod's as below and have just upgraded the Multec injectors to Ford Blue Top 24lb injectors as the car was cutting out at around 4000RPM (after I installed the supercharger). The Blue top injectors solved this problem but the car doesn't feel as quick when I put my foot down at low rev's. It runs okay but feels like it is bogging down a bit. I'm thinking that it may be because it is running too rich with the new injectors and that I may need to re-program the computer?? Any feedback would be appreciated as here in New Zealand you can't find mechanics that know these engines. Cheers Craig Vortech A-Trim centrifugal supercharger Front mount intercooler MSD6530 Digital Programmable Ignition MSD Leads Bosch III (Ford Blue top) 27lb injectors Walbro fuel pump Vortech rising rate fuel pressure regulator Cooler plugs K&N Sequential blow off valve Full length headers Twin 2.5inch exhaust with x-pipe Cat’s and all emission gear removed Right hand drive!

Bit of a understatement.
You installed a S/C and haven't changed the stock tune ?
I suspect your tune would be way off with the S/C alone ;let alone the bigger injectors
Did you change the MAP sensor to accomodate boost?

>.>....

Correct the tune on the ECM has not been changed since the supercharger install.

Fuel is of course increased from FMU and timing retarded automatically by MSD.

From what I read in the Vortech install manuals and on the Blowerworks site that sells the kits you could get away with the standard ECM.

I have just purchased an Ostrich but haven't received it yet.

Any suggestions would be appreciated.

MAP sensor has not been changed. Will this stuff up tune under boost? What should I install?

I only run NA but my understanding is you have to change to a 2 or 3 bar MAP sensor that will read boost conditions.

Best you ask the experts here;
wealth of tuning knowledge
http://www.thirdgen.org/techboard/dfi-ecm/
http://www.thirdgen.org/techboard/diy-prom/

Just fitted an LM-2 fuel/Air ratio monitor and when I put my foot down the AFR is going as low as 10.5 which explains the loss of power due to rich mixture. What sort of AFR should I be seeing under acceleration?

When I receive my Ostrich are the key changes I need to make fuel flow rate and duty cycle. New to this so plenty to learn!

By doing an injector change without tuning ;in your case you have richened it up across the board which obviously helped your lean cond at the top end but has made it excessively rich at the bottom as well