GM extreme timing set and opti

[94formulaLT1]

i would like to get the extreme timing set from GM but it is for 95-97 f-bodies only. I have a 94. i was told if i got the timing set, i would have to get a 95 optispark. right? from what i read this timing set is pretty good but is it worth all of the trouble?

[TraceZ]

i would like to get the extreme timing set from GM but it is for 95-97 f-bodies only. I have a 94. i was told if i got the timing set, i would have to get a 95 optispark. right? from what i read this timing set is pretty good but is it worth all of the trouble?

You'll also need a 1995 timing cover as well as a cam with the correct dowel pin on it for the vented opti.

Plan on changing the opti, cam, timing cover and timing gears/chain.

[94formulaLT1]

You'll also need a 1995 timing cover as well as a cam with the correct dowel pin on it for the vented opti.

Plan on changing the opti, cam, timing cover and timing gears/chain.

im starting to think the extreme timing set isnt worth my time, i think a new lt1 timing set would suffice. what do you think?

[Injuneer]

The "vented" Opti is a good upgrade. The LT4 Extreme Duty set is overpriced, but reliable (if installed correctly). It's unfortunate that the combined price of all the pieces comes up to something north of $600, making it a bit expensive unless you really want the two upgrades. I opted for the full conversion - vented Opti and ED timing set, and it was pricey. But I'm also running a solid roller cam with high spring pressures, and a 7,000+ RPM redline, so the ED set seemed important.

[94formulaLT1]

The "vented" Opti is a good upgrade. The LT4 Extreme Duty set is overpriced, but reliable (if installed correctly). It's unfortunate that the combined price of all the pieces comes up to something north of $600, making it a bit expensive unless you really want the two upgrades. I opted for the full conversion - vented Opti and ED timing set, and it was pricey. But I'm also running a solid roller cam with high spring pressures, and a 7,000+ RPM redline, so the ED set seemed important.

you see, i want to do it right the first time. i would like to get the ED timing set, but i am unsure of what all i will need. taking my engine apart is a learning experience for myself. that is why i ask you guys. i am not worried about the money, atleast for the most part. like i said i want to do it right the first time. so if you guys tell me what i need, i will get it so i can do it right. if you think about it, your saving money by spending more now than buying the cheaper item and having it break..so that is why i like the more expensive items. sooo right now my car is in the garage with half of the engine laying on the table. i need to get going on this project if i plan to finish it before the end of may, which is the car show. for now i need to get a cam, timing chain, opti...then i will need headers, heads, TB, injectors and whatever else i will need. i have it split like that to help me keep track of what i buy.


also...you can answer this seperately but i will need bigger injectors. yet i dont know how much horsepower i will be making. next year i plan on doing the 383 stroker kit and a procharger, so i will be making a #%@! load. so my question is would it be possible to buy "bigger than needed" injectors and put a fuel pressure regulator on my car so i could regulate the injectors. do i have the right idear of the fuel pressure regulator? as always thanks for your help.

[Injuneer]

You only need injectors, not a new fuel pressure regulator, at least until you get the blower. You can go oversize and as long as you tell the PCM the correct injector size, it can adjust the fuel/pulse width calculations to get the A/F correc. NEVER "tune" with an AFPR. Use it to increase the flow rating of the injectors, not "tune".

A rough guideline on injector sizing for a normally aspirated engine is flywheel HP time 0.07. For a 500 flywheel HP engine, that gets you 500 x 0.07 = 35 #/HR injector. You could put a set of 36# injectors in virtually any engine from 300-500HP, and it will run fine. If you think you might go to 600HP in the future (NA), you could think in terms of 42 #/HR. The only possible downsided of a grossly oversize injector is a difficulty in getting the pulse width short enough to provide a smooth idle.... but you won't have any problem up to 36#.

Even if you go to a blower, you don't want to tune with the AFPR. You MAY want to consider a step up in fuel pressure when you add the blower, simply because it gives you more flow on the injectors. Maybe step up from 43.5psi to 58psi. Now your 42# injector is a 48.5# injector. Some blower kits use a boost referenced FPR or an FMU that adds on to the fuel return line to raise pressure with boost. Again.... the right way to do it is to "tune" with the PCM, not the fuel pressure.

Keep in mind.... changing injectors is very simple mechanically. And any change that requires larger injectors is going to require PCM programming. So if you bought a "medium" injector for running NA, you could always sell them later and put the money toward the larger ones when you added the blower.

[94formulaLT1]

You only need injectors, not a new fuel pressure regulator, at least until you get the blower. You can go oversize and as long as you tell the PCM the correct injector size, it can adjust the fuel/pulse width calculations to get the A/F correc. NEVER "tune" with an AFPR. Use it to increase the flow rating of the injectors, not "tune".

A rough guideline on injector sizing for a normally aspirated engine is flywheel HP time 0.07. For a 500 flywheel HP engine, that gets you 500 x 0.07 = 35 #/HR injector. You could put a set of 36# injectors in virtually any engine from 300-500HP, and it will run fine. If you think you might go to 600HP in the future (NA), you could think in terms of 42 #/HR. The only possible downsided of a grossly oversize injector is a difficulty in getting the pulse width short enough to provide a smooth idle.... but you won't have any problem up to 36#.

Even if you go to a blower, you don't want to tune with the AFPR. You MAY want to consider a step up in fuel pressure when you add the blower, simply because it gives you more flow on the injectors. Maybe step up from 43.5psi to 58psi. Now your 42# injector is a 48.5# injector. Some blower kits use a boost referenced FPR or an FMU that adds on to the fuel return line to raise pressure with boost. Again.... the right way to do it is to "tune" with the PCM, not the fuel pressure.

Keep in mind.... changing injectors is very simple mechanically. And any change that requires larger injectors is going to require PCM programming. So if you bought a "medium" injector for running NA, you could always sell them later and put the money toward the larger ones when you added the blower.

that does help, i didnt know the PCM was that versatile. im real excited to start buying parts so i can get this project rolling but the cam deal has me pinned. i wish i could find the right cam for my application, that is the only piece that has me at a dead stop. maybe since you guys somewhat have an idear of what im aiming at, maybe you could give me some advice. thanks

[fastTa]

If you use those Trick Flow heads that have 62cc combustion chambers, they will lower your static compression ratio almost a full point if you make no other changes to the bottom end. So until you get the supercharger put on, the motor will be very soft no matter what cam you put in. In fact the larger the cam, specificaly a longer duration, the lower your dynamic compression ratio becomes. That means less cylinder pressure and less power. You might want to consider a different head if it will be a while before you install a blower.

How soon do you anticipate putting the blower on?

[94formulaLT1]

If you use those Trick Flow heads that have 62cc combustion chambers, they will lower your static compression ratio almost a full point if you make no other changes to the bottom end. So until you get the supercharger put on, the motor will be very soft no matter what cam you put in. In fact the larger the cam, specificaly a longer duration, the lower your dynamic compression ratio becomes. That means less cylinder pressure and less power. You might want to consider a different head if it will be a while before you install a blower.

How soon do you anticipate putting the blower on?

you know, i was thinking the same thing, i was starting to rethink the whole 62cc trickflo. they are nice heads, you have to admit that, and who knows, i could still get them next year, but maybe i should go with something a little smaller. but i dont want something to small, i would still like to run nitrous. this is why i ask you guys before i buy.. so what would you recommend to me if i still wanted to run nitrous, maybe 150 shot? i didnt plan on doing the 383 stroker and blower until next year, like this winter when i put the car in. i wish i could do it all now, but im using barrowed money as it is now.."credit card?-no problem" (thats off of home alone..) so i gotta watch what i spend for the most part, but im doing it right the first time. i know how to use credit cards and everything, right now my car is on one and ive been paying that for almost 1.5 years..so wish in one hand and $#*! in the other and figure out which weighs the most..

i still have a a little bit before i buy heads, so im not in too of a hurry, but sooner the better to know. first i need to figure out what cam would fit my specs.

[94formulaLT1]

hey fastTA, clear up some of your PM in your box

[fastTa]

hey fastTA, clear up some of your PM in your box

Will do. We need more than 70 allowed stored messages, that 70 limit comes too fast.