robertfrank

iTrader: (27)

Many questions have been asked lately that need a quick condensed answer so here's some help.

What intakes can I use?.....................
Many different choices can be made for an intake for tbi. Check this thread for less redundancy.
https://www.thirdgen.org/forums/tbi/...check-out.html
But I will say that a very popular choice going right now is the 7101 Edelbrock RPM intake.


What cams can I use?...............
This questions get asked alot and here's some of the most popular choices in the TBI world.
The stock cam is called the "peanut cam" and from a performance stand point it sucks, although with some ingenuity with other mods a TBI car can run decent with the stocker. These are listed from smallest to largest.

Stock L03-L05 camshaft 10088155 179/194 - .350/.384 109 LSA

Stock cam W/1.6 rockers 10088155 182/197 - .373/.410 109 LSA

L31 or B-body LT1 camshaft 10243779 191/196 - .418/.430 111 LSA

88-89 L98 camshaft 10066049 207/213 - .415/.430 117 LSA

93-95 LT1 camshaft 12551705 202/207 - .450/.460 116 LSA

ZZ4 camshaft 10185071 208/221 - .474/.510 112 LSA

Production LT4 cam 12551142 203/210 - .476/.480 115 LSA

LT4 Hot cam 24502586 218/228 - .492/.492 112 LSA


What heads can I use?................

There are many different cylinder heads that can be used in your TBI controlled vehicle. Here are the most popular choices.

Ported stock "187" heads
ZZ4 or "113" heads
"059" or 305 vortec heads
Standard "062" or "906" vortec heads
Ported "081" TPI heads
Trickflow 53cc aluminum heads
World Products S/R Torquers

It all depends on how much money you have to spend. With the 059 or 305 vortecs you still have a 58cc combustion chamber, no real milling involved. But you need an intake to match because your stock one WILL NOT bolt-up.
With the 062 or 906 heads they will need to be milled down a bit to get the proper combustion chamber size or you'll lose compression and like the 059 heads a new intake will be needed.

The ZZ4 heads will need to be milled down even though they are 58cc due to the aluminum dissipating heat faster and thus a loss in power will result IIRC. Also with the ZZ4 heads your intake will need the two middle bolt holes elongated due to the angle being off between the 87-88 model years.

The Trickflows seem to be a good choice for a head but at a price of almost 1200 dollars it's not really a "budget" head. The S/R torquers from what I understand aren't that great of a head and they also weigh a ton due to the extra meat left for porting.

So this leaves our stock heads. In recent years the stock 187 or Swirl port head have been shown to have great gains when ported. If you don't want an engine that breathes hard above maybe 5200 rpms and you want more torque through out the powerband stick with a set of ported 187's. Stock TPI heads don't flow that well in stock form but ported they flow pretty well.


What about exhaust?.....................
Hooker 2055's are basically the number one used header in the TBI world. They are some of the best emissions legal headers you can buy. A good cataylitic converter is a must if you live in an area that requires emissions testing. There are many different cat-backs that can be used. It really depends on taste but be sure to use A 3-inch catback. here's a list of popular cat-backs.

Hooker Aerochamber
Flowmaster
Borla
Magnaflow
Edelbrock SDT
GMMG chambered exhaust


What about tuning?...............
Honestly at this moment I'm not an expert at this subject but there's many here that can help you get started.In the last few years, Tuning for TBI has come leaps and bounds over anything that has come before. Check this thread for better details.
https://www.thirdgen.org/forums/tbi/...free-tune.html

The best thing in the TBI world is the EBL flash, a good Wideband O2 sensor and tunerpro rt. Tuning can be done with cheaper tools but with The EBL flash and a wideband even a novice like myself can get a good start.

That's the most I can say about the ENGINE side of the puzzle. I hope this helps. If anyone else wants to add anything feel free.

RFmaster

'frank

Nice summary - well done! You may want to add RHS 12333 Iron head with 200cc intake port volume and 50cc chamber to your list of 'head' candidates.

//RF

Doc_G

iTrader: (1)

great post, this is why when it comes time to rebuild I'm leaning toward a 335 tbi. (stroked 305 but you guys already knew that) From what I've gleaned lurking and reading here I could see 300 or so rwhp, and thats good enough for what I'm wanting in a dd.

ruberbanman126

This should be in the stickies!!!

robertfrank

iTrader: (27)

You will get flamed for the whole "stroked" 305 idea. While honestly it's not the most cost effective route for an engine build but if you want to do it I say go for it. That's what this "hobby" is all about. Trying new things to see how they work. If you don't like it, Try something else. You can make an easy 300hp from what you already have without stroking your 305.

robertfrank

iTrader: (27)

On to some other things.......


Drivetrain. Whats a good torque converter for me?

A fairly cheap and popular swap for a torque converter for your TBI vehicle is a L35 96+ 4.3 s10 converter 24202310 which you can get from www.gmpartsdirect.com for about 201.80 plus shipping. It's a K-140, 2,025 RPM stall converter which is a good replacement for the wimpy (1300-1600 rpm) stall that is already in your car.

Another good and VERY cheap upgrade for your auto transmission is the Sonnax AS1-01K TV cable corrector. It's really just a piece of plastic with a spring on it you place on the detent cable to increase the tension on the cable it usually runs about 12 bucks. Here's a good thread about it.
https://www.thirdgen.org/forums/tran...nax+kit+spring

Aluminum Driveshafts. Are they worth it?

Some say yes while others say no. Honestly freeing up rotational weight anywhere in your car is beneficial, even if it is in small amounts. I noticed that my engine felt "free'er" at highway speeds and a vibration I had dissapeared. The stock ones weigh about 15-18 lbs while they aluminum ones weigh around 10-11 lbs.Aluminum drums are also a popular but hard to find swap. Ebay is going to be your best bet on this one. It frees up about 5lbs EACH side of rotational weight.


Underdrive pullies. Do they work?
I believe they do. I know I had a slight increase in power switching to mine but it depends on what exactly are you looking for. Here's what mine look like but be warned mine were EXPENSIVE due to the fact I bought the whole setup. I know that the whole march setup including brackets pullies and hardware weighed LESS the just the stock PULLIES alone. That to me made this swap worth it.


But really if you want more power there are better and more smog legal ways of doing it.I did it because I'm a neat freak and I don't have emissions testing in my area.


Gears. What gears are good for me?.................


Our cars came from the factory with some wimpy highway gears. 2.73 for auto's and 3.08's for the sticks. With a peg leg open rear end to boot, no wonder these cars feel so slow. If you really want a good kick in the pants improvement in drivablility and performance these things need to go. Switching to a posi or limited slip is an absolute must for these cars.

3.42's for an auto and 3.73's for the T-5 crowd.

Depending on an other mods that might have made your engine breathe better I.E. intake, headers and such I would even go 3.73's for the auto and 4.10's for the sticks. It just depends on how far you want to go.

Icarus 402001

I

I think he meant "stroked 350", not "stroked 305"

LoudmouthSS

iTrader: (6)

dont forget about the 601 heads (53cc chambers and a nice compression boost)

Doc_G

iTrader: (1)

Well to be honest, Robert I was originally thinking 350 but I found a link to a website on here about stroking the 305 and the power potential the little engine has. I dont want to spend a ton of money on the rebuild (figure 1500.00 tops) of the engine and at the same time I'd like to have something not many folks have. The 335 Idea just kind of fits for what I eventually plan my 91 to be. I dont want/need massive amt's of power as it will be a dd and I personally have never heard of stroking a 305. I do agree with your statement about it being what this hobby is about. I have also contemplated going the roots style blower route as well. But thats going to require more research and contemplation as it will nearly double my projected engine build budget.

robertfrank

iTrader: (27)

Just the stroker kit from www.enginekits.com for their powerhouse 335 kit will run you almost 1000 dollars by the time it's all said and done. Then machining and having the engine built if you don't know how to do it will cost another 500-1000 dollars on top of that. You can buy an L31 short block from www.sdparts.com for $1,099.95 12556121 plus shipping. there's a thread in the top of the stickies which is perfect for this.
https://www.thirdgen.org/forums/tbi/...i-buildup.html

But like I said before, If you want to do it. Do it, I'm not knocking on you like most people here will. It's your engine and it really hasn't been done before so have at it. I think it should be an interesting build if pieced together right. As far as a roots style blower and TBI you can do it. I believe one of our members here has done it (V8 Astro Captain) Albeit I don't think it was in a thirdgen, but from what I understand he was able to do it. The EBL Flash can tune for boost, so if you wanted to go that route it can be done.

but let's not turn this into a stroker a 305 flame fest. I wanted to start this thread to get some of the more brought up and mostly asked questions.

Doc_G

iTrader: (1)

Wow I saw the stroker kit listed as 650. I was unaware of the balancing needed as well. Hmmm that paints a bit of a different light on the subject. As for the engine building itself, I can do it I'm sure. Its not (or atleast it appears not from my reading) all that different than building a carb'd engine. I've done that before a few times. The block machining if needed will cost me a little bit of nothing (yay for family members in machine shops) Where I figure I'll need the most help is in the tuning and chip burning department. For that I'm thinking the local dyno shop can take care of that for me. I appreciate you taking the time to help me along with your informative posts and suggestions. In the end I may end up building the 350 instead, but I'm going to shoot for the 335 first. As with any project financial consideration will be the final determining factor. But right now this is just wishful thinking as the suspension/brakes will be receiving my wallet and tool's attention first. No sense building the go before the whoa IMHO.

83 Crossfire TA

iTrader: (2)

woops... wrong thread...

nimrod_sixty9

Thanks, Ive been wondering about this. How bad will it affect MPG? Good deal quicker? What vehicles came with them (Im a u-pull-it guy)?

robertfrank

iTrader: (27)

IIRC correctly If you look on the main page in the tech articles it should tell you the best options for replacement rears. You can get a rear from ANY 3rdgen Fbody. I know that the V6 cars cam from the factory with 3.42's and the Iron duke and L69 cars came with 3.73's. 4thgen rears works as well but they stick out further about and inch or so n the sides. As far as gas mileage Iknow when I changed over to my 3.42's my mileage got BETTER around town due to the fact of not having to put as much foot into the throttle.

nimrod_sixty9

Thanks for the info, already started a thread refering to an LS1 rear. I believe 3.42. What Im worried about is the speedo. I dont want to tear into my tranny to make it right...

89_RS

Hey robert,

Thought I'd lend a hand and link in a site with a wealth of data on the LO3:

http://goingfaster.com/spo/praisetbi.html
http://goingfaster.com/spo/spo_technology_central.html

Also, for those considering the idea of stroking a 305, heres the technical specs you'll need to know for it. As far as I know, 1986 and earlier 305 engines had 2 piece rear main seals, whereas 1987 and later 305 engines had a 1 piece rear main seal.

Stock engine specs:
3.736" bore, 3.48" stroke, 5.7" Connecting Rods, 2.45" Journal Diameter-Main, 2.10" Journal Diameter-Rod

Now, for the stroker specs:
3.766" bore which is .030" over stock can be as high as .060" over stock for a bore of 3.796" (its not reccomended by anyone here to bore a 305 more than .030" over stock), 3.75" stroke, 5.7" Connecting Rods. The journals may require machining depending on what crank you use. Always make sure to have the entire rotating assembly balanced and the block clearanced properly.

Reason I listed the specs is that some of you may want to use forged parts for stroking a 305. There are no forged stroker kits out there for a 305. I've found a forged crank and rods from Lunati that can be used in stroking a 305 and a set of forged pistons from Weisco for this purpose. An all forged setup like the one below will run about $2000 before machining:

http://store.summitracing.com/partde...N&autoview=sku
http://store.summitracing.com/partde...1&autoview=sku
http://store.summitracing.com/partde...3&autoview=sku

Hope this helps.

TonyC

iTrader: (1)

Could one of the mods sticky a new post with these links that says "WARNING, THIS PERSON IS CRAZY"? Seems this website comes up once every half year or so.

Feel free to delete my reply after doing said posting

89_RS

He's not crazy, rather the man that wrote that is fairly level headed. He actually did a fairly in depth analysis of the 305 TBI and provided his results. They are accurate, fairly unbiased, and do provoke thought while stating that the already understood fact that a 305 TBI isn't as economical as a 350 when it comes to mods. I confirmed everything I read on that website here on TGO.

TonyC

iTrader: (1)

I apologize for the lack of detail in my previous post, but let me elaborate. Black Echo's web site has been around since 2001? 2000? earlier? I'm not sure, but every 6 months or so someone reads it and posts it up in the TBI boards. It honestly wouldn't be so bad if it wasn't entirely too overdramatic and outdated. If you think that's unbiased, you have a long education in engineering ahead of you. To put it in perspective, here's Pablo (one of the earliest guys to actually get some performance out of a TBI car) protesting its posting in 2002:
https://www.thirdgen.org/forums/tbi/...ould-get.html?

My main gripe with the page is that it doesn't actually have any results, figures, numbers or anything that would substantiate any of the claims made! We've had no evidence of him actually doing any of the "in depth" researched modifications that are preached on that site, just a few outdated, generic magazine builds. Do a search for "Black Echo", he's posted maybe a handfull of times?

This board is a living, breathing example of how to get a little bit of power out of these engines. If you want mod examples, look to any of the buildups that have been done recently by Fast355 or any of the old examples put together by NJSPEEDSTER, Pablo, JPrevost, camaroracer1992, Dewey316, Blackbird305, or myself; all have been in the 13's and 14's (I'm sure I'm forgetting plenty of people, I apologize). There are a lot of good buildups going on currently as well, robertfrank's car should be a pretty stout runner! Also Keep an eye on graebZ28's buildup, it should be knocking on the 12's with no issue. The times have changed since that web site came out, especially tuning wise (thanks to Rbob and others for that). Mods, feel free to delete this, just please can we not reference the goingfaster web site anymore?

89_RS

I wasn't saying the guy was un-biased, he has to be if he's preaching the mod a 305 stuff. But what made it fairly unbiased is that he said these same mods would net you more gains on a 350.

The reason I found the website useful was for 2 reasons: actual technical specs on the 305 and the fact that someone was willing to discuss possible ideas on how to mod a 305. Yes, his articles are quiet out of date and he himself provides no actual data of things he did himself, but his articles do provoke thought and critical analysis of the 305. That more than anything has been of great help to me in getting me steered in the right direction on my current project. Just because I took a different lesson away from that website than others doesn't make the site bad.

I do agree that he is overdramatic, the site is outdated, and that people on here have far more technical data and real world experience to back up the idea of 305 builds. But that website does provide noobs with a good starting point for projects. It was the first article I read and it refered me to this forum. And I took what I learned from that article and used it with what I've learned here to begin my planning my project.

Not trying to be argumentative, just telling you how that website helped me.

robertfrank

iTrader: (27)

Ok now that we've got the whole "Black Echo" ordeal out of the way here's my next topic.



Spacers.


From throttle body spacers on to injector pod spacers have been a hotly debated issue as if they really make any real power. Well I can contribute the following due to the fact that I have both.

Injector Pod Spacer.

Can be purchessed on ebay from "xtremefi" for about 15 dollars.

Does it add the 12-15hp that it has been claimed to do. NO it does not.
what it does is raise the pod up more to both create alittle more breathing room for the TBI and also instill more of a "efficient" cone pattern for the fuel to enter the TBI unit. You can do this cheaper by just getting 2 pod gaskets and stacking them. same effect. just get some longer cheap allen head screws from either home depot or true value for like 15 cents.


TBI spacers.

Do they work? Yes and no
you can find MANY different styles from Ebay, Summit, jegs, CFMtech, turbocity, etc. etc

I have recently installed one on my vehicle and it is NOT just a bolt on and go affair. The best way to install one is to get a few washers to lift up your throttle bracket to keep the cable geometry the same. not to hard but I'll write a detailed "how to" later.

What I have noticed with this spacer is slightly better fuel economy and better low to mid range torque. not alot but it is noticeable.

Now the downside to this.

It seems that when my car is cold it "lugs" alittle more than it used to. once it warms up it's not present. Maybe a tuning issue I'm not sure yet. Other than that I'm "pleased" with it but the debate on taking it off is still in question.

Much more to come...........

RFmaster

Hey Robert

Let me start by stating that I have no validated performance numbers, but I have used 1" spacers in my two carb to TBI conversions. The reason for 1" (Mr. Gasket) spacer is to move TB high enough to gain sufficient clearance for fuel lines to clear Holley 300-49 backside. On a GM intake TB mount base is very small (area wise), but on a Holley it is identical to square flange 4-BBL carb. In fact looking at it and after measuring unused mounting holes it appears that 300-49 design was borrowed from square bore carb applications.

Increased intake volume suppose to improve throttle response, but I have no means of quantifying that. Regardless of what numbers might be the latest conversion ('70's Nova) is a blast to drive and gets great fuel mileage when loud paddle is being treated gently.

I have not used pod spacers - no comment.

//RF

dctrumpet

iTrader: (10)

The only true way of finding out if a 1/4" injector pod spacer, 1/2" or 1" TBI spacer makes any difference at all is pre and post dyno on the same machine with the same tech.

I will throw my fraction of a cent in, lol.

My opinion and answer is NO it makes zero to very very little horsepower gain. It does make some torque gain and airflow of course.

The reason why i know this is not from personal experience, but from two friends in southern CA. They set out to be the "TBI Myth Busters" lol. Kind of like what i did with the fuel pressure regulator springs that are sold as 10-25psi ranges etc. I busted that myth big time.

Anyway, they ran their setup 3 times without any spacers then with the 1/2" tbi spacer 3 times as well. No rear wheel hp gain at all. They then added the 1/4" injector pod spacer and again, no gain in rwhp. Both had a very slight increase in torque.

They then tested it at the flywheel the same exact way with and without spacers and amazingly there was about a 4 hp gain when both spacers were added.

Yes, they tuned each time. This took them about 2 days to do everything. 90rs with a stock 305tbi and an 89 camaro with a relatively stock 350tbi. Since then they tested it on a few pickup trucks. About the same results.

I am waiting on them to give me their dyno sheets for proof, but they have no reason to lie.

Well, according to those who sell the spacers, the hp gains should have been about 20hp or more.

If there are definite dyno results out there by those who manufacture these please let us see the results.

They have not tried the patented "power plate" as of yet, but I know Scott well enough from CFM-Tech that if he says something then he means it. So if CFM-Tech states an increase in hp i would almost put $$$ on it.

Again, just my wee little input.