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Discussion Starter · #1 ·
OK so i joined this site when i spun a main in my car in order to learn as much as possible about our vehicles,now i have some last minute questions,i decided to have block bored to a 355,motors almost done and in the put together stage,i have edelbrock performer heads and cam,roller rockers,lt4 modeule,ported intake and throttle body,and im addin a 2800 stall converter,now i've left the stock exhaust manifolds and have stock injectors,if i drop this motor in without a pcm tune will it run right?? or with the cam and heads does it NEED to be tuned?? Also will the stock valve covers fit over the new RR's? I just need a starting point before i get carried away on engine mods,thats why im stayin with stock injectors,also its just a weekend driver and not a track car,in the future im sure i will add headers and 30+ pound injectors which i know will require a tune,and a bunch of other pieces,but i haven't been whole since my cars been down and i really want the motor in and then add parts and fine tune later,thanks for any info.
 

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You will NEED to get it tuned to get te most out of it. It may run, it may not run, and if it does, it'll run like crap till you get it tuned.

Stock Valve covers usually need to be clearanced for roller rockers.
 

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You will NEED to get it tuned to get te most out of it. It may run, it may not run, and if it does, it'll run like crap till you get it tuned.

Stock Valve covers usually need to be clearanced for roller rockers.
I run GM RR and Comp Roller Tip with Stock Valve Covers.
No problems..

Your car will run fine with the stock tune.
But for best performance go to pcmforless.


D
 

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you most likely will have idle/surge issues with a aftermarket cam. It should run but you may have to keep some gas on to keep it idleing.

IMHO you should get a tune.

your 24 lb injectors may be OK...but you may find at "sustained" WOT they hit 100+ on duty cycle indicateing a larger injector is needed

simple mod for stock valve covers

http://golenengineservice.com/html/lt1_facts.html#valvecmod
 

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Discussion Starter · #5 ·
ok so if i get it in and have idle issues where i have to gas it to keep it runnin the only fix for that issue is tune my stock pcm?also i was readin on some deletes,and questioned the throttle body bypass,is this to keep the hot coolant from heating the preferrably cold air from entering the intake?and also read about the egr being blocked when upgrading motor,now mine works fine,they say if u block this u will NEED a tune,also the AIR pump delete,are these thinks i should worry about or just stick to my plan to get the motor in and run it then in the future worry about these deletes? I've soaked in alot of info for the last month and im tryin to weed through it
 

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ok so if i get it in and have idle issues where i have to gas it to keep it runnin the only fix for that issue is tune my stock pcm?also i was readin on some deletes,and questioned the throttle body bypass,is this to keep the hot coolant from heating the preferrably cold air from entering the intake?and also read about the egr being blocked when upgrading motor,now mine works fine,they say if u block this u will NEED a tune,also the AIR pump delete,are these thinks i should worry about or just stick to my plan to get the motor in and run it then in the future worry about these deletes? I've soaked in alot of info for the last month and im tryin to weed through it
im in the process of putting my motor back together right now and i was asking the same questions. if you are gonna do the deletes, do them now because its a whole lot easier to do them when the engine is not in the car than it is when everything is put back together. i just did a top end swap on my car and im tightening everything back up now and it was so easy to pull all the a.i.r. crap off with the accessories not installed and it was hella easy to do the egr because i had the intake out of the car. it was a pain in the a** getting the egr crap out of the car when i was doing disassembly. so...do the deletes now and yes the egr will have to be tuned out of your computer.
 

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Discussion Starter · #7 ·
so did u just not put the pump and hoses back?and just leave the bracket bare? when i was readin about the air delete it looked as easy as plug the line and unplug the relay,but i wasn't sure if you had to leave the hoses,if i don't need that system it would be no problem to leave it out of the assembly process
 

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Nevermind the cam and injectors, with a stock tune on a bored out TB (52 mm, right?) you will fry your transmission in short order.

Put a stock 48 mm TB on the car until you can afford a tune.
 

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Discussion Starter · #9 ·
As far as tranny goes,im addin a 2qt deeper pan,and also added another cooler and will remove the lines from radiator,will i still have issues,i know the key to the tranny is keep it cool
 

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Discussion Starter · #10 ·
It's been a well known fact for nearly a decade that failing to reflash the PCM for a larger throttle body rapidly leads to a transmission rebuild.

You have been warned.



Next time add some insight,or elaborate,tell me why,is it b/c it makes the trans shift sooner? At this time i haven't FAILED to do anything,i don't even have the motor in yet but im tryin to make sure all the surprises are taken care of,If all you have to say is "you have been warned" next time just don't reply,i need help not criticism,thanks
 

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The transmission line pressure will be too low, allowing mucho slippage on the shifts. The transmission line pressure is controlled by the throttle position sensor at low rpm, and the bigger throttle body will let too much air in - which means more torque - at very small throttle openings (< 20%) when the line pressure is very low.

Oh, and you don't want to remove the radiator from the transmission fluid cooling circuit. Just add the cooler to the return line from the radiator.
 

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Discussion Starter · #12 ·
Thanks stone great info,so, another question,i've heard the BEST way to tune the motor is dyno with a laptop,then chart the results and then tune the pcm,correct? maybe im makin this too difficult but seems to me like a lot of varibles that you DONT wanna miss or you will have malfunctions and even damage,so what do u do trailer the car to a dyno shop until its tuned with the new performance mods? or just send in the pcm where they can get close and call it good? as i've said before its not a race car,but i want it to be right so i don't damage engine/trans,thanks too all who have stuck with me i appreciate the info
 

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Thanks stone great info,so, another question,i've heard the BEST way to tune the motor is dyno with a laptop,then chart the results and then tune the pcm,correct? maybe im makin this too difficult but seems to me like a lot of varibles that you DONT wanna miss or you will have malfunctions and even damage,so what do u do trailer the car to a dyno shop until its tuned with the new performance mods? or just send in the pcm where they can get close and call it good? as i've said before its not a race car,but i want it to be right so i don't damage engine/trans,thanks too all who have stuck with me i appreciate the info
True, dyno tuning is almost the best way (tuning at the track is better), but you're getting into the law of diminishing returns here. If you're never going to take it to the track, you'll never miss the last couple of tenths the dyno/track tune will eke out.
 

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Discussion Starter · #14 ·
Perfect,so to sum it up,send off my p/ecm to have it tuned,tell them the parts i have installed and deleted,and it will be fine? I was doin some readin about doin this all yourself but it looked like spend money on many different parts, cables and software, but almost wouldnt be a bad idea if you were constantly changin parts or readin codes,or i'd be really nice if somone on this forum was close to san antonio and had all the tuner software that was willing to help me out:D thanks stoney you have been very helpful,how do you like the 355 in your car?
 

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Perfect,so to sum it up,send off my p/ecm to have it tuned,tell them the parts i have installed and deleted,and it will be fine? I was doin some readin about doin this all yourself but it looked like spend money on many different parts, cables and software, but almost wouldnt be a bad idea if you were constantly changin parts or readin codes,or i'd be really nice if somone on this forum was close to san antonio and had all the tuner software that was willing to help me out:D thanks stoney you have been very helpful,how do you like the 355 in your car?
That's pretty much it. And if your tires are taller/shorter than the stock ones, I'd mention that too, so they can re-calibrate the speedo while they're at it.

I liked the 355 just fine until I wrecked the car!
 

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OP

you have quite a few mods going on and most will require a PCM adjustment so advise whoever you use to tune it all the things you are doing. typically the tuner has a "form" you fill out showing what the mods are and they make a tune to accomadate.

any tuner assumes everything is working right i.e. on the TB rebore the TPS is about .67vdc closed and 4.5 vdc full open and IAC counts are 30-35. quite often aftermarket TB's need to have the hole drill mod or stock rebored TB's need to have that hole SLIGHTLY larger. you need scan software to confirm wtf the IAC counts are. a volt meter can be used to read TPS but scan software also reads that.

if after you have everything togeather with a mail order tune you have idle issues than you may have to look into the IAC counts. Some crack the TB blades open "slightly" to resolve this and then have to drill/slot the TPS case to move the TPS back into range...I don't subscribe to this but some do resolve their idle issues with modified/aftermarket TB's this way.

if you do not get a PCM tune for the mods you won't hurt anything just starting the car....it will run like crap and most likely will not want to idle on it's own. driving it is another story...as mentioned the tranny will not work correctly and can suffer damage as a result if you do continue to drive the car...not immediately so you could drive it to a dyno or short trips if you wanted to
 

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Discussion Starter · #17 ·
ok so what if i do everything mentioned but without the aftermarket tb for the meantime,will driving with the stock tb on my performance parts be fine?just slightly air restricted?all in all i don't HAVE to have it, it is my garage vehicle,so it wouldn't hurt me to bolt on all the parts start it for the 20 minute breakin period,then send off the pcm.

Or while its down,send off the pcm NOW that way when the motor is in, were ready to go? what is the best option? or did i just answer my own question
 

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Or while its down,send off the pcm NOW that way when the motor is in, were ready to go? what is the best option? or did i just answer my own question
^^^^^^^^^^^ bingo

starting the car with the stock tune for 20 min breakin won't hurt anything ...... but having a mail order tune for the mods will be better.

you can keep the 52 mm on....if it is the stock rebore it will run better than a aftermarket one without the IAC air passage hole.

you have to tune for a larger TB anyway...just add that to the list when you advise your tuner.
 
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