305 Performance
Morley
02-23-2005, 12:41 PM
Anyone else got any comments, suggestions??
Yes, but you won't like them.
The first thing is exhaust..it is the most restrictive part of the engine's breathing.
A larger throttlebody on a 305 is wasting money. The factory stock throttle body will supply more air than the 305 can use.
Larger injectors won't do you any good..they will supply too much fuel. The prom chip is programmed for a set size of injectors, change them to larger/smaller and the computer is no longer supplying the correct amount of fuel.
A set of
Vortec heads will also require a special intake manifold, and for TPI there is just 1 source and it costs $400. You are better off porting a set of non swirl 305 heads.
Pullies....snake oil, they can cause more trouble than they are worth.
Cam....well, not yet.
Before you begin trying to get more out of your little 305, get a cheap laptop, free scanning software http://www.moates.net/index.php?cPath=33 , A prom burner and prom adaptor http://www.moates.net/index.php?cPath=25 and a .bin editor. Learn about prom burning, get to know what is what on a prom chip and how to go about making changes and knowing what the changes do and affect. Try here for a good place to start http://www.eecis.udel.edu/~davis/z28/
Then it is time to think about more extensive mods like high flow intakes, cams, 1.6 rockers and the like. No "custom" burned prom you buy will ever be 100% correct, only someone that has the car at their disposal can hope to get the tune right.
Yes, but you won't like them.
The first thing is exhaust..it is the most restrictive part of the engine's breathing.
A larger throttlebody on a 305 is wasting money. The factory stock throttle body will supply more air than the 305 can use.
Larger injectors won't do you any good..they will supply too much fuel. The prom chip is programmed for a set size of injectors, change them to larger/smaller and the computer is no longer supplying the correct amount of fuel.
A set of
Vortec heads will also require a special intake manifold, and for TPI there is just 1 source and it costs $400. You are better off porting a set of non swirl 305 heads.
Pullies....snake oil, they can cause more trouble than they are worth.
Cam....well, not yet.
Before you begin trying to get more out of your little 305, get a cheap laptop, free scanning software http://www.moates.net/index.php?cPath=33 , A prom burner and prom adaptor http://www.moates.net/index.php?cPath=25 and a .bin editor. Learn about prom burning, get to know what is what on a prom chip and how to go about making changes and knowing what the changes do and affect. Try here for a good place to start http://www.eecis.udel.edu/~davis/z28/
Then it is time to think about more extensive mods like high flow intakes, cams, 1.6 rockers and the like. No "custom" burned prom you buy will ever be 100% correct, only someone that has the car at their disposal can hope to get the tune right.
Genopsyde
02-23-2005, 01:04 PM
Yes, but you won't like them.
The first thing is exhaust..it is the most restrictive part of the engine's breathing.
A larger throttlebody on a 305 is wasting money. The factory stock throttle body will supply more air than the 305 can use.
Once the heads and manifold are changed, that stock TBI will choke the engine.
Larger injectors won't do you any good..they will supply too much fuel. The prom chip is programmed for a set size of injectors, change them to larger/smaller and the computer is no longer supplying the correct amount of fuel.
Once the heads are changed, the stock injectors will starve the engine of fuel, and a dyno tuned prom chip will adjust the fuel curves accordingly.
A set of
Vortec heads will also require a special intake manifold, and for TPI there is just 1 source and it costs $400. You are better off porting a set of non swirl 305 heads. He also mentions World Products heads, which are far superior to vortecs and non swirl heads.
Cam....well, not yet. why not, the cam has to be included in the prom programming. Kinda wastes money if you get one programmed, then change the cam and have to get a new one programmed again...
The first thing is exhaust..it is the most restrictive part of the engine's breathing.
A larger throttlebody on a 305 is wasting money. The factory stock throttle body will supply more air than the 305 can use.
Once the heads and manifold are changed, that stock TBI will choke the engine.
Larger injectors won't do you any good..they will supply too much fuel. The prom chip is programmed for a set size of injectors, change them to larger/smaller and the computer is no longer supplying the correct amount of fuel.
Once the heads are changed, the stock injectors will starve the engine of fuel, and a dyno tuned prom chip will adjust the fuel curves accordingly.
A set of
Vortec heads will also require a special intake manifold, and for TPI there is just 1 source and it costs $400. You are better off porting a set of non swirl 305 heads. He also mentions World Products heads, which are far superior to vortecs and non swirl heads.
Cam....well, not yet. why not, the cam has to be included in the prom programming. Kinda wastes money if you get one programmed, then change the cam and have to get a new one programmed again...
89IROC&RS
02-24-2005, 12:26 AM
primary shortcoming of the 305 block is the size of the bore. it shrouds the valves and restricts breathing. If you are building a low rpm engine then it will still work just fine, but anything looking to make decent upper rpm power should be made with a 350. aside from that all the same rules apply. make it easier to breath, fight friction, poor combustion, and thermal power losses, and you will make more power.
Morley
02-25-2005, 09:01 PM
Anyone else got any comments, suggestions??
Well, I gave a bunch of feedback, but someone deleated the entire post.
Well, I gave a bunch of feedback, but someone deleated the entire post.
Genopsyde
02-25-2005, 09:03 PM
it wasn't deleted, it was separeted from this one, this thread isn't for feedback.
To be more specific, the thread is meant for tips on 305 performance, your post pretty much said all the suggestions that Damone said are useless, which they aren't. The last part of your post with the ecm programming links are all you should've put.
To be more specific, the thread is meant for tips on 305 performance, your post pretty much said all the suggestions that Damone said are useless, which they aren't. The last part of your post with the ecm programming links are all you should've put.
Zaddict
03-13-2005, 10:46 AM
Whenever you are altering the breathing capability of the engine you MUST consider both intake and exhaust. And when considering intake you must consider the size of the lungs. The lung capacity is vital to getting performance out of your setup. You simply cannot pump whatever you feel like into something that can only hold so much.
Remember there is too lean and too rich, but there is also flow and cc size. trying to flow 8000cfm into 6000cfm intake is futile and trying to combust 70ccs in a 60 cc is just as futile.
Know what you're working with and then bring that flow capacity to its peak.
Remember there is too lean and too rich, but there is also flow and cc size. trying to flow 8000cfm into 6000cfm intake is futile and trying to combust 70ccs in a 60 cc is just as futile.
Know what you're working with and then bring that flow capacity to its peak.
Morley
03-13-2005, 11:56 AM
Once the heads and manifold are changed, that stock TBI will choke the engine.[/b]
No it won't, the stock TB will flow well beyond 800 CFM, more than enough for a well built 383.
Once the heads are changed, the stock injectors will starve the engine of fuel, and a dyno tuned prom chip will adjust the fuel curves accordingly.
Thats not how it was written, the LAST thing mentioned was a prom and unless you plan on breaking 350 HP the 19 lb injectors will work just fine.
He also mentions World Products heads, which are far superior to vortecs and non swirl heads.
And no where did I make any mention of the world heads, just the Vortec's. But lets examine the world heads...SR's? They are just that Stock Replacement. A set of ported non swirl 305 heads will flow better than out of the box SR's and save you $$, considering you'd probably already have them or can buy them very cheaply.
why not, the cam has to be included in the prom programming. Kinda wastes money if you get one programmed, then change the cam and have to get a new one programmed again...
Why not a cam yet? Not if you are piece mealing it as it was written, if you are doing it as an entire package, then by all means, getthe cam at the same time. And I can't stress this enough....Getting an "aftermarket custom prom" is hit or miss at BEST. You can't just give someone the specs of your engine and components and expect to get a properly tuned prom. The only way a prom can be properly tuned for a specific vehicle is if the person doing the prom has the vehicle at their disposal to run and drive.
No it won't, the stock TB will flow well beyond 800 CFM, more than enough for a well built 383.
Once the heads are changed, the stock injectors will starve the engine of fuel, and a dyno tuned prom chip will adjust the fuel curves accordingly.
Thats not how it was written, the LAST thing mentioned was a prom and unless you plan on breaking 350 HP the 19 lb injectors will work just fine.
He also mentions World Products heads, which are far superior to vortecs and non swirl heads.
And no where did I make any mention of the world heads, just the Vortec's. But lets examine the world heads...SR's? They are just that Stock Replacement. A set of ported non swirl 305 heads will flow better than out of the box SR's and save you $$, considering you'd probably already have them or can buy them very cheaply.
why not, the cam has to be included in the prom programming. Kinda wastes money if you get one programmed, then change the cam and have to get a new one programmed again...
Why not a cam yet? Not if you are piece mealing it as it was written, if you are doing it as an entire package, then by all means, getthe cam at the same time. And I can't stress this enough....Getting an "aftermarket custom prom" is hit or miss at BEST. You can't just give someone the specs of your engine and components and expect to get a properly tuned prom. The only way a prom can be properly tuned for a specific vehicle is if the person doing the prom has the vehicle at their disposal to run and drive.
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