DanMac

I have a 305cc TBI in my 89' bird. I want to learn the in's and outs of these car's before I go do something as drastic as attempt a motor swap.

My car is my daily driver and I have what I think are fairly modest performance goals. I wan't to get my 305 to put out 300+ hp. I mean it's a v8, it shouldn't be that hard? or should it?

Will new cams and exhaust headers do the trick? How would get get a 305 up to 300+ HP?

seanof30306

iTrader: (4)

dude, you sound exactly like i did a year ago when i bought my 89 firebird 305 tbi.

there is a TON of information on that in this tbi forum. i suggest you do what i did. start at the beginning of these posts, read every one that seems to be on point and take notes as you go. it's interesting as hell and you'll have a great idea as to what it'll take when you get caught up.

DanMac

Sounds like a plan, might as well get started tonight.

thanks for the reply

305RSlc

It's gonna be more than hard to get to your goal if you stick with the crap casting swirl port heads that are on the 305. Get yourself some cheap vortecs, or even the world products 305 specific heads, a SINGLE plane intake (help you out in upper RPM) a holley adapter plate, the holley 670cfm TB, and a good cam. The LT4 hot cam it a good choice to start with or call comp cams. After that, headers and full exhaust and you should be relatively close to 300hp. I am gonna second reading as much as you can possibly read before starting anything. These boards are packed with info, and when you do something you wanna make sure you are doing it right the first time and not screwing something up.

Dewey316

a few things.

1) start now with computer work, tune the hell out of your car stock. then do small upgrades, see how it effects things, and tune the hell out those combo's, learn how the car reacts to timing/fuel changes. you will need this information later

2) the only way to do this, is to go with a fairly 'radical' cam for this, since our cars are a MAP (speed density) system, the fueling and spark in the computer is determaned by a VE table, any change in the efficency of the engine, makes these tables not work right, changing cam and heads will make a big change to what is needed in these tables, talking about a drastic change like this will require a lot of time and effect into tuning it, thus why i suggest you start with #1

3) the rest of the car needs to be up to snuf. your stock fuel system likely won't support that HP, your going to need a good hi-flow fuel pump. the exaust also won't support that, headers and cat-back will be needed. cam/intake/head selection will be determined by your needs. do you need to pass emisions? is this a street car, a strip car, a road racer, or an auto-x car. if you plan to race it, do you have a specific class/type that you are planning on? if so, you need to look at the rules for that class, to descide what mods you can/cannot do.

4) suspension work would also be advised, along with the appropriate gears, and adding a posi unit. you need to hook up your new found power, having the power there doesn't do you any good, if it just goes into tire smoke.

5) tranny -- at high power levels, chances are a stock untouched tranny is going to be short lived. if your a manual, thing will probably go downhill fast, especialy if you drive it hard. if you have an auto, your going ot need a new torque converter. with a large cam you are going to move the power band up quite a ways, you need to change your stall speed to get you into the power quick.

that should get you started, there is alot there to consider, you need to make the whole car work as a system, you can drop 5k into an engine, to find out the computer can't handle it, the suspension sucks, and you tranny blows. that is not alot of fun to find out after you used up all your fun tickets on the new mill.

ShiftyCapone

iTrader: (7)

Dewey hit it right on the head. You really need to do the computer work now so that down the road you understand why your car changed the way it did. There are a lot of weak links on these cars and most of them need to be taken care of together. Once you start adding heads and cam you run out of fuel. SO then you replace the pump, re-tune, and now your stock TBI unit can no longer support the power. So now you are doing the research to get a 454 TBI or holley 670 TBI on top of your motor so that you can tune again. Now you need tradaction..... As you can see it is a never ending cylce of chaznging parts. These cars are great platforms and have the capability to accept trillions of aftermarket stuff. The stock stuff is just grabage and needs to be replaced if you want to hit your goal.

seanof30306

iTrader: (4)

yes. if i were starting over from scratch, i'd do chip tuning before i did anything else. one thing that stuck out when i first got on these boards was how many cars with 373 posis, headers and free flowing exhausts, intakes, lt1 cams, ultimate tbi mods, etc still ran in the 15s. i thought it was mismatched parts, but i've come to realize it's chip tuning.

if you approach this from an "old school" perspective like i did, you start with the things you understand like exhaust, intake, cam, etc., holding off on getting into the chip tuning till you absolutely have to. big mistake.

once you're able to burn those chips, you can maximize the power potential and efficiency of every change you make. someone (i believe it was dewey) started their chip tuning when the car was almost completely stock and picked up a half a second in the 1/4 mile (if i remember correctly) with that only. there was someone else who got into the 13s with the stock heads and cam .... but lots and lots of tuning.

it's hard to do. if you're a newbie without a lot of computer skills, be prepared for lots of headaches. ha ha ha. i'm just now getting ready to start datalogging. we'll see what happens.

it'd be nice if you could get them burned by someone else. the truth is, i believe you can (despite popular opinion). you could send your datalogs to someone with a lot of expertise at this and have them burn your chips. over the course of several back and forth adjustments, the chip would end up being "on". the problem is that you'll need to go through that process again after every change you make. it's just too expensive.

Dewey316

yes, i actualy picked up closer to a full second. and 6mph.

it just takes practice, as much as i wish i could tell people mail order works, and that in 4 or 5 chips, you can have a good one, it just doesn't work. i have burned probably 60 chips now, for my stocker. and i am still working at it. you need more than just datalogs, they don't tell the whole story, especialy at WOT, i am getting ready to buy a wideband, i already use a tazzo (g-tech) along with 'how it feels', datalog, and 1/4 mile data from the track. this all plays into it, the butt dyno lies, the datalogging lies, you have to learn how to sort it out using a combination of tools.

seanof30306

iTrader: (4)

what wideband are you going to buy?

Dewey316

probably the inovative, i have a cutout that i am going to install, so i would like ot weld the bung in when i do that

seanof30306

iTrader: (4)

also, dewey, i do believe you can get it pretty right with an offsite chip tuner, as long as they're good enough. there's a guy on here named mike crews with a 383 tpi that's almost into the 11s and makes 400 rwhp, and he's only had around 10 chips burned for his car! his combination is pretty mild, he's only using 3.23 gears and lets the transmission shift itself. he's obviously pretty close to dead on in his tuning to make the numbers he does.

you said you'd burned over 60 chips for your car so far, but wasn't a lot of that learning process? i'd think if someone were an expert, they'd be able to do it with less. i have a buddy who is in a club of crown vic/mercury marauder fanatics. twice a year, this former ford engineer comes to town and sets up appointments at a ford dealership that has a dyno. he does a drivearound datalog, and two dyno pulls and guarantees an improvement in horsepower, driveability and economy or your money back. these guys line up around the block! my buddy has a mustang ecm and intake, gt40 heads, etc on his. picked up 30 hp and 6mpg on the tune. watching the chip guy work, it was obvious that he knew just what to look for and just what to do. wish there was a comparable guy for our cars.

again, i think the person burning those chips makes all the difference in the world. the problem isn't that you can't find someone to do it, it's that every time you make a change, you'll have to start the process over.

DanMac

I'm actually really looking forward to PROM programming, I'm a programmer by trade, so the thought of being able to program my car seems like a lot of fun. I'm pretty sure I wont have too much trouble getting the datalogging and chip buring stuff set up. However knowing what to change is another thing? How can you tell if you need to advance/retard your timing in a given rpm range? or increase/decrease fuel supply? It's all very mysterious to me at this point.

seanof30306

iTrader: (4)

i'm in the same boat, brother! if you go to the diy efi forum, there are lots of guys there who can help. since you're a programmer, you'll be able tun understand the gobbldygoop they respond to your questions with ... something that is still totally beyond me.

and dewey, i've been looking at the lm1 too. will you be able to use the data from that directly, or will you have to do the changes manually? i'm still unclear on this, but don't you use a program written by jprevost that reads your datalogs and adjusts the spark/fuel tables for you accordingly?

seanof30306

iTrader: (4)

the first thing you need to do is turn off the speed limiter. mine damn near killed me this weekend!

there's this long, sweeping, increasing radius turn on "the buford connector" near where i live. the previous owner of my car was an autocrosser and had done a lot of suspension work. i've done a little more and it's amazingly stable in high speed cornering. my previous record on this corner was 100. decided to break that at around 3am sunday morning. the speed limiter cut in right in the middle of the tightest part of the corner and i damn near went around!

talk about a surprise!

Dewey316

yes, i use jons program, but that only works at part throttle, in PE mode it won't do squat. it also doesn't adjust timing. that is where the WB, and track data helps. the stock o2 is very inaccurate, so using the WB to nail WOT fuel is a must. timing is best done at the track, give it the timing that gives you the best MPH.

morrow

go to chevy thunder.com

Saabster

iTrader: (2)

You're right, about 1 hp/cu in is not too hard on a small block. If you want to stay with you LO3 heads (165/140 CFM), you're going to need a cam in nearly the 220 duration (note, this is more than an LT4, more in line with an LT4 HOT cam) and spin it to almost 6500 rpms, and everything in between to support that.

I will repeat what everyone else has said and that's that tuning is really going to make or break this thing. A well tuned stock LO3 with a bolt on exhaust will, IMO, womp on a LT4 cammed up TBI that hasn't been tuned properly. There are many options: chip burning, the excellent EBL system, and megasquirt. All have advantages and disadvantages. I personally am going megasquirt as I believe it has the greatest flexibility, but it also has the greatest initial investment (not $$$, it just takes a lot of knowledge to set one up.)

So no one can really give you exactly what need, you have to look at the knowledge yourself and piece together what you need to get where you want to go. The greatest asset of the small block, it's potential and parts availability, is also it's greatest danger. As the saying goes, it gives you just enough rope to hang yourself.

ericjon262

wow guys, this thread is almost 6 years old.

Saabster

iTrader: (2)

Damn, that always gets me.

CamKid1992

not sure if you still need help but i got me a pair of trickflow 23 heads for my 305 new cam 412 lift headers exhaust and a very good tune with a hypertech chip and im around 310 im sure i forgot something o and msd ignition.

Saabster

iTrader: (2)

What sort of duration and intake are you running? Also, 310 measured where?

CamKid1992

after posting this last night i was curious and got it dynoed today. it pulled 327.8 at the rear wheels.. the intake is the holly/weind stealth ram with adj fuel rail. here is the link to my cam

http://www.summitracing.com/parts/LUN-54742/

ericjon262

Thats TPI not TBI. imprssive none the less that you made 327 HP out of a 305.

thomas1976

Isent it HSR?

CamKid1992

true never thought it like that and i had the tbi for a long time. with the edelbrook intake and you can get a bigger truck throttle body im sure you could get close.

kodiak27

how did u get a series 40 muffler when it only has one in and 1 out i think u used a series 80

ericjon262

or just ran a single exhaust and not a fake dual!

Saabster

iTrader: (2)

I'm going to do that, so half the exhaust doesn't have to turn nearly 180 degrees.

dimented24x7

iTrader: (2)

Flowmaster has a base 3" exhaust for thirdgens that has just a single, hide-away stock type rear exit on the drivers side (I assume this is the one referenced above). I have it on my car with a hooker maximum flow muffler instead. The flowmaster 30 series (or whatever it comes with now) that came with it was a bit restrictive.

steven hecker

did you use the Hypertech 122362 - Hypertech ThermoMaster Computer Chips or was it a different model chip?

CamKid1992

just for the record if your going to beef up a 305 with 300+ hp you could put the 335 stroker in it. or you will need some kind of bottom end i did not and had 327hp and well i spun a rod bearing. just make sure you have a strong bottom end.

ericjon262

why stroke a 305, that has got to be the biggest waste of money I have ever heard of, you can by running 350's all day for cheaper than just the stroker kit.

Fast355

iTrader: (2)

I have no problems running the under-dog engines and making them run very well.

My stock bottem end held over 350 RWHP on a NA 305 and constant 6,500 rpm abuse.....A properly setup STOCK bottem end has NO issue holding power. Just make sure the bearings have the proper clearance, the rotating assembly is well balanced, and you have some arp rod bolts. Maybe they put jello in the L03 bottem end, but I doubt it is much different than the L30 lower end my engine started out as.

My older 305 was built better than the L30 lower-end was stock for stock.

I have had my fair share of lower-end problems, but most of the problems are from using fatigued parts or parts that were not up to the application. Out of round, out of balance, thin casting, stuff like that.

I just found the limit of my stock Dodge 4.7 lower end..... At about 280 RWHP and 6,500 rpm, it fatigued a rod, which let go at about 3,500 while driving around town. A light bang and a small screech later...I was on a tow truck. I was able to make it out-run stock Hemis fairly easily though. 0-60 in 8.5 secs from a heavy 5,500 lbs quad cab.. Still had the stock clutch fan, stock exhaust manifolds, and stock catalyst on it even.

http://www.youtube.com/watch?v=MmE3qRAtaXc