Im new to the tpi cars, had a 83 crossfire Z when i was younger , then a 92 rs that was a carbed drag car , now i have 98 TA, and my newest addition that picked up a 85 Z28 tpi car off my buddy that had a blown 305 tpi , he replaced it with a goodwrench 350 longblock he had sittin around, is there any thing i need to change like pcm or injectors to prevent any damage im gonna use the car for a dd

thanks in advance

 

You need a 350 knock sensor
350 electronic spark module
22 lb injectors.
350 prom chip

Everything else will work fine.

What injectors did he have? I would imagine it would be greater than 19lbs if it was blown.

 

i believe the knock sensor is the same for the 305 and 350. when i swapped out my 305 for my 383 i kept the same knock sensor. also i would use 36 lb injectors to keep the duty cycle down. third i would go to street and performance at...

http://www.hotrodlane.cc/indexhome.html

and have then custom make you a chip. they charge like 100 bucks and it's about a 1000x better than super chips or something like that. ask for bear he really knows his ****!

 

thanks for the info, by blown i meant the engine threw a rod and cracked the block(blew up) sorry i'll be a little more descriptive next time

Would it damamge the engine if it were driven like a 20-30 miles with the stock 305 stuff on the 350, its got a MAF but its so old i doubt its adaptive to change like ob2 pcms

yeah try gettin info for TPI's off LS1 guys its like your speaking latin well i guess im gonna start learning latin

 

The knock sensors are not the same. They have different part numbers and the 305 is way more sensitive.

 

i wouldn't drive it if i was you. it will run super lean!

 

It will actually run super rich... not lean. Just do not go too high in the RPMs that is when it would plateau.

You can use the 19 lb injectors and have a prom chip tailored to the injectors. I would still recommend you to use the 22 lb injectors.

 

how do you figure it will run rich? you are running a 305 tune on a 350. a 305 obviously uses a lot less gas than a 350 and the computer may try and compensate for the car not having enough fuel by dumping some in but there is only so much it can adjust.

i understand you can use the smaller injectors but the thing you want to look at is the duty cycle (what percentage of the tie the injectors need to stay open to supply the amount of gas needed to operate the motor, the lower the duty cycle the easier it is on the injectors) you generally want to keep the duty cycle less then 80-85%. you CAN run it on a 22lb injector but i would recommend going larger.

 

While the computer is trying to compensate the ratio during idle and lower RPMS the computer is dumping a butt load of fuel in it, and since you are not in the upper rpms in most of your driving yes... you will run rich.

 

Ok i'll just baby it on the way back to my house, then let it sit until i get prom burnt, im just gonna get a set of accel 24lb injectors and pickup a knock sensor for 87 5.7 not hard I work at a parts store

but where should i go for the prom burn?

once again thanks guys

 

even though i disagree that it will run rich i would trailer it either way. running pig rich is as bad as running lean.

http://www.hotrodlane.cc/indexhome.html

go to that website and call them for the prom 200 bucks and hands down it's the best tune I've had for my car. even better then the custom tune i had made on a dyno.
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i do agree that it will dump fuel but it will be limited to the amount the computer can compensate for the difference in fuel needed and the amount the injectors can dump into the cylinders. there is only so much the computers can compensate and the injectors can dump into the engine.

 

hey everyone
well...i have to say i agree with nelapse...i am having the same problem with my 86 iroc. it was originally a 305 car, and my buddy built a 350 roller motor for it. .i have had problems with it like you wouldnt believe...it runs RICH. i cant even get it to start now cause it apparently ruined my plugs. When it last ran i barely got it to start....revved it up..and it died. I did have accel 24lb injectors in it...now im back to 19lb cause i thought it would help it. I know if I go out and install new plugs it will run okay for a while...till it floods it out.

 

get a tune and clean the plugs but don't try and run it until after you do that. as i said running the motor rich can hurt it just as much as running it lean will hurt it.

 

is the spark control module and knock sensor really necessary to change? can i get away with having a chip burned and be good to go? about how much is it to have it done with that website shown? one guy on here said $100...another said $200.

 

i don't think you need to change the knock sensor or the spark control module. i used the same ones on my 383 that i used on my 305. the tune is necessary and it will cost 200 on the site above but it is better than chips for 4x the price i can testify to that from first hand experience. they definately know their stuff there.

 

hey..thanks a lot...i will have to call them...just out of curiousity...would you recommend this prom for my car? the motor is pretty much a stock 350 just has a roller cam. http://cgi.ebay.com/ebaymotors/86-89...QQcmdZViewItem

 

i wouldn't do it with my motor. remember when it comes to modding your motor you get what you pay for 99% of the time.

ask for Bear when you call them there. if he works there still he really knows his ****!

 

Let's put the knock sensor in perspective.
305 knock sensors are more sensitive.
350 knock sensors are less sensitive and work fine with 383's since they are the same bore they are fine.

I had a 305 knock sensor on my 355, the knock sensor and electronic spark module screwed the timing up soo bad that it made my car run 2 seconds slow on a quarter mile.

I replaced it, raced it again, worked the way it is suppose to. The engine even sounds better now the timing is where it should be.

So sure, some people can say YES you can use it, it worked well on my car. However, this is YOUR car. You want to do it right?
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Also $100-$200 for a custom prom is a rip off. There are tons of people on this site that will tailor you a prom for $20 bucks. There is no "tune" unless you are on a dyno or on a track constantly measuring and adjusting your progress. Something you cannot simply do over the internet.

 

whatever dude you obviously know it all! I'm not trying to argue! the one i have on my car is the one i was instructed to buy when i swapped my 305 tbi to tpi and it works fine! the timing is absolutely perfect! I've had it on a scanner and everything shows correct!

would you trust some random person to rip you a prom? or would you rather have a professional do it? i'm glad you know everything because if it wasn't for you and your infinite knowledge no one would ever be able to do anything to their car.

 

Thank you for sharing.

 

well...i called that company up today...they said they only do 1990 or later tpi computers. they prefer to convert to speed density rather than use mass air.

 

Again... contact someone here on the prom boards and pay them to burn you a chip.

You input things like

350 305
auto/ manual
injector size
rev limit
EGR disable
Speed limiter
lock up speed for TC

etc

Just talk to someone and they can hook you up.

 

i made that switch. it will run fine for ANY length of time. it will just run like crap. while the 19# injectors and the prom set for the 305, with the 350 sucking more air at idile it will run very rich, then once you get to upper rpms the 19# injectors will reach there limits and it will run lean. nelapse was dead on in his first post. thats all you need. it will run with all the 305 stuff just dont dog it too bad. like nelapse once i change that i took off a full second. a 350 prom is made to work with a 350 knock and ESC mod and the injectors. thats all you need to know

 

Too bad I am going carb now :P TPI is holding me back I am tell'in you!