Z2EIGHT

I'm very aware that 305s are not monster powerhouses, and with gas prices it doesn't seem that farfetched.

I have a '92 Z28. The car's an Auto with a 305 TPI. It has 91,xxx miles with full exhaust, 24# fuel injectors, drop in K&N filters and some MSD stuff.

I am aware of power loss with an auto but it's to much hassle for me to switch. Can I make 300HP from my engine n/a? The car is just a DD and I want to play with some of the new mustangs.

-Peace

Orr89RocZ

iTrader: (20)

at the wheels or on the motor?

on the motor its very easy to get there. at the wheels it will take a fair amount of mods but can be done.

I'd start with full bolt ons, from headers to aftermarket TPI setup or ported stock base with SLP runners or big tube runners from TPIS/AS&M/etc. Got to let it breathe.



To ensure 300hp on motor, you'll need a cam. Nothing huge but definately a step or two over stock.
300hp on motor is like a full bolt on L98 350.. or about 250whp or so. stock 305 TPI in good shape with an auto may make 200whp. probly more like 190 for some models. 350's are 210-220 or so. Full bolt ons on a 350 make 30-40whp. On a 305 i'd say its more like 20-25 since TPI doesnt choke the 305 as much as the 350.

So you will need another 20whp atleast from a cam which isnt asking for much. A cam a tad smaller than a Lt4 hotcam or similar will give you that number.

A bigger cam like cc503 may make 300whp on a ported head combo. 300whp will really need decent heads, a nice sized cam and good tune and probly some rpms over what TPI is capable of, you'll need a siamesed setup i'd say but its possible a big tube setup will work

Then tune it as it will need it badly, that will give you a decent boost over stock.

Z2EIGHT

I'm talking on motor.

BluFBdy

iTrader: (1)

why stop at the motor? its the RWHP that counts. and correct me if im wrong but getting an aluminum driveshaft, synthetic gear oil in the rear, roller rockers etc, should also increase RWHP because you arent losing as much power through friction?

Orr89RocZ

iTrader: (20)

yep reduced friction will get more hp to the ground

Fast355

iTrader: (2)

Ported aluminum ZZ4 heads, Reworked TPI with oversize runners, Production LT4 camshaft, Tri-Y design headers, full exhaust system, and DIY Prom tuning will get you near your 300 FWHP goal, while keeping near stock driveability.

Z2EIGHT

Well I don't know very much about cars so thanks.

So besides motor mods, what are some good mods to reduce the friction?

Orr89RocZ

iTrader: (20)

you can free up power with underdrive pullies and electric waterpumps. less accessories you turn, the less hp is taken from the motor

Lighter parts are easier to turn as well, so the motor will not take more power to turn those things. Lighter flywheels/flexplates, lighter driveshafts, etc.

More efficient torque converter for auto trans will help get more power to the ground.

Z2EIGHT

How bout bypassing/removing the smog pump? I only drive the car to school so I'm not really worried about cops.

Orr89RocZ

iTrader: (20)

smog pump doesnt take much to run... you'll be lucky to gain 1-2 hp if that...probly wont make a difference. I just deleted mine to clear engine bay space. I noticed NO gain at all. And it only took off like 5 lbs from the motor

Z2EIGHT

I'm thinking about taking the CAT off along with the Smog Pump. You think that might gimme like 5hp?

Orr89RocZ

iTrader: (20)

cat may help some, smog i dont think will give much.

Z2EIGHT

I gotta find a way to get the CAT off, and what to put in its place.
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I gotta find a way to get the CAT off, and what to put in its place.

BluFBdy

iTrader: (1)

doubtful. pulling your cat and pump probably will do nothing for you, nothing noticable atleast. SKip the cheap tricks and try real mods like suggested above. Recuce your drivetrain friction and lighten the load on your engine. your smog pump will make little to no difference. If you pull the pump and not the cat you will eventually fry your cat and plug it up. Get a set of good headers, a nice exhaust, a new cam, different gear oil etc. Just get a high flow cat. problem solved

IROCmonkey

Is it possible, absolutely. Is it a simple matter of throw a few parts and drive away, absolutely not. Those numbers can be reached through the means described variously above.

A quick solution to gain more power is to replace your exhaust from the heads back: headers, larger y pipe, hi flo cat, full catback, and better flowing muffler. That alone will not net you an extra 100hp though. Better cam and heads will get you further along, by this time you'll need to do some PROM tuning.

Unless your cat is plugged up, simply removing it will not do much performance wise. Plus no shop will do it with out replacing it. Get a good flowing aftermarket cat, unless you can fab your own tubing.
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lol masterdisaster and I were typing the same response at the same time :lol

Z2EIGHT

Thanks

Orr89RocZ

iTrader: (20)

gutting the cat will make your exhaust louder tho

Z2EIGHT

When I bought the car, the cat was off so I really want to take if back off.

MidnightBlue07

I'm also wondering is my setup right now close to the 300hp mark at the motor or what do I need now to get there.

BluFBdy

iTrader: (1)

forced induction is always a possibility. You'd probably overdo your 300 mark but a few more ponies never hurt anyone

Z2EIGHT

This is the intake I have now.



Would a CAI be better? I heard that stock intake is actually very good and I don't need a CAI. What should I do? In that intake are 2 K&Ns btw.

Orr89RocZ

iTrader: (20)

stock intake could be opened up to flow more but should be MORE than enough for a 300hp 305

BluFBdy

iTrader: (1)

unless you have a large H (an A in some cases) on your hood, or your engine needs it very badly, a CAI does not belong on a thirdgen, they have pretty good intakes as it is.

somehitng i didnt think about but what if you bought a holley stealth ram setup? i have no experience in TPI yet so if anyone wants to chime in on this that'd be great, or you could get your heads and intake ported a bit, just dont go overboard

kowboy59

iTrader: (8)

I love mine. HSR gets two thumbs up. My problem now is i got a k&n direct tb air filter. But now i have nitrous on its way. What should i do?

Orr89RocZ

iTrader: (20)

I dont think a full bolt on 305 will get 300hp on crank. My L98 put down 254 which i believe is around 300-310 on crank with full bolt ons. Thats 45 more cubes than a 305 so thats gotta be atleast 20 more hp and alot more torque. lol my desktop dyno shows roughly 11hp difference, but who knows how accurate that is, but it does show a huge loss of torque for a 305 vs a 350. To confirm this, i've seen 355 to 383 dyno graphs using same heads/cam and the 383 didnt make much more power, just made more torque.

I still think a 305 with bolt ons will only be lucky to hit 275hp on motor with stock cam/heads.

you'll need a small cam but definately a cam to reach 300 on motor
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cant you run the TPI style plate system on that car, and go back to the stock style TPI air intake setup? just gut your air boxes and it will feed that motor with plenty of air.

kowboy59

iTrader: (8)

When you mean gut you mean cut holes or just literally gut? What i really want is the tpi tb plate. I seem to not find one but idk.

Batass

Check this out. RHS did this build and they used AFR heads. Didnt hit 300hp.

http://www.hioutput.com/tech/290hp/290hp.html

Its an EGR intake, but I imagine it would flow more top end than TPI. Cam is a little small.

If its more power you want, give up on that engine. If you just want to be different, well then thumbs up.

Orr89RocZ

iTrader: (20)

cut the bottom of the TPI air box out completely so the air filter is exposed to fresh air. Even run air ducts from the grille to get a ram air effect

Orr89RocZ

iTrader: (20)

That makes me upset that they spent all that money on the block/heads and run a stock L98 cam. that pure energy cam is pooop You can easily run a bigger cam and still pass emissions. That motor should be more like 330hp with the right cam and still pass emissions.

Does show you can build a potential strong running 305. Just needs a good cam

Z2EIGHT

Sorry but I'm a complete noob when it comes to cars. Can you sum up what a cam is, and why I need one for? I thought all cars come with cams? Everywhere I search I get these long scientific explantions. Whats a small cam do that my regular one can't?

Thanks,

BTW: I also read that the HSR on a 305 doesn't work too well. On 350s they do great.

The 305 is a project that I want to complete before highschool. (Junior) It is sorta like a comeback to insults from Ford Fans and BBC Bullies. I like being different and doing something great with an underdog engine. The truth is that I've had my L98 from a C4 Corvette for sometime now. (Sits in garage, collects dust) But the little 305 I drive to school has grown on me, to the point I love this engine.

Does anyone know if the 305 is a light engine? I got some good ideas for it in the future and I want to know if its a porker or somewhat lights. Small CID = Light?

-Peace

Orr89RocZ

iTrader: (20)

oh my.... you have alot to learn.

Cam controls how the valves open and close on the engine. every engine has a good specific valve opening/closing timing event for best efficiency and power. Stock cars with poor flowing heads and intake manifolds use small cams since those motors dont need alot of air. A smaller cam is one with less duration, or the amount of time *measured in crank degrees* that the valves stay open. So they let in less air and therefore make less power and dont rev really high.
Large cams have more duration so the valves stay open longer thus being able to supply more air to make more power.

Thats the basics

Batass

I dont think you'll reach 300 fwhp with the stock heads. You'd have to put a pretty big cam in. I wouldnt dig too much into that engine. You can get to about 275 with cheap easy stuff I believe. Stuff that would swap over to a 350 someday.

1 5/8 headers with a bigger exhaust system, better muffler
Better air induction filter/tubing/cold air
Adjustable fuel pressure regulator, turn the pressure up 10 psi IIRC
Air foil for the throttle body
Advance your timing, stock is weak.

That should take you to around 250hp. If you feel ready to try a cam swap, I think you could pick up a stock LT4 cam pretty cheap. That would take you to around 275. Just enough to beat a mustang of a comparable year.

Youd have about 800-1000 bucks into it. If you still want to go faster, throw some nos on it.

IROCmonkey

TPI is 40-45PSI stock.

305 and 350 blocks weigh about the same. No more than a few lbs difference. All Gen I SBC's are weight about the same and share the same external dimensions. The difference in CID is in the bore and stroke.

Can you make it lighter? Sort of, you can use lighter, better parts for the internals and reduce the mass of the rotating assembly (crank, rods, pistons) for more effeciant use of combustion. But this gets expensive and provides limited returns.

Z2EIGHT

So I want to be looking for an LT4 cam? Is it going to fit well or am I going to have to get it machined? I have money, it's just custom work that's a pain.

Hey Orr89, That pic you posted of the gutted air intake. What year is your car, and are they all the same? I thought about doing that but people driving 80s thirdgens were explaining it to me and I didn't know if my car was setup different. BTW: I have these wires in this black plastic tubing thats on top of the grey plastic parts that you cut out. Did you have this, and where did you place it?

Batass, right now I have Edelbrock Longtube headers (Not sure what size, they were on the car) and a 3 inch flowmaster exhaust. Cats coming off soon. (For sound )

Do those Airfoils really work? I've read that they don't do a thing and are a waste of money. Is it even worth if it does work?

-Thanks

Orr89RocZ

iTrader: (20)

yes most TPI setups will have that style intake that you can cut out. i had a section of wiring harness that ran thru that area and i tucked it under the center cross brace/filter support that i didnt cut out.

Batass

Airfoils? Dunno, I just heard that was a popular bolt on. One of the chevy magazines did a top ten best budget bolt ons for TPI, LS1, and LT1s. Look it up, it was good. Posted power improvements and cost. I think better gears was the best improvement.

The LT4 cam is a direct bolt in. You have to pull your intake manifold to pull out the lifters. Its a bit of work for a novice. But I think getting headers on is one of the hardest things to do. Patience gets short.

Z2EIGHT

Thanks for the help guys. I'm finally getting my project setup. Let's keep it up!

Orr, after I cut out the plastic. What is that foil tubing for, how did you install that, and is it worth it? (Even if it's only a few hp) Also is there any real benefit to cutting out that plastic cover?

Thanks