bolt on
03-12-2010, 09:25 AM
#1
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bolt on
i have a 1995 z28 had the engine rebuilt and bought a slightly larger cam and a 57mm throttle body now after all this my mech tells me it wont run right with these add ons with out changing the computer or going witha a intake and carb i did notwant to change the whole car ,he said that i would have to put a new stock cam ,sounds like im getting the shaft now sure can anyone shed some light on this for me ??
03-12-2010, 11:04 AM
#4
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With regard to the cam, you need a "tune". There are numerous sources for a "mail-order" tune - you send your PCM, they program it and send it back. If you have relatively simple/common mods, its pretty easy for them to get it right. There are people here making well over 500HP with a "tune" on the stock PCM. You do not need to go to a carb. You do not need a new computer.
What throttle body did you install... never heard of a 57mm (48mm is stock, 52, 54 and 58 available aftermarket)? Did you have the intake manifold opened up for the larger throttle bores (stock intake openings are 52mm)? Generally, just going to a larger throttle body will not take a "tune", unless you have an automatic trans, and the shift points need to be adjusted for the changes in line pressure resulting from the larger open area for any give throttle position.
For a mail order tune check "Trifecta" in the "Supporting Vendors" list, linked at the top of every page. He can send you a "loader" with a new program, so you don't even have to send him your PCM.
What throttle body did you install... never heard of a 57mm (48mm is stock, 52, 54 and 58 available aftermarket)? Did you have the intake manifold opened up for the larger throttle bores (stock intake openings are 52mm)? Generally, just going to a larger throttle body will not take a "tune", unless you have an automatic trans, and the shift points need to be adjusted for the changes in line pressure resulting from the larger open area for any give throttle position.
For a mail order tune check "Trifecta" in the "Supporting Vendors" list, linked at the top of every page. He can send you a "loader" with a new program, so you don't even have to send him your PCM.
04-19-2017, 02:07 PM
#5
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Re: bolt on
sorry its been a while had to stop on my project for a few years ,but question is the same so your saying it s needs just a performance flash or program? it is a holly after market 36lbs injectors and headers and a six speed .any input would be helpful
04-19-2017, 05:35 PM
#6
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Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
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Re: bolt on
You can gain 10-15 HP with a tune on a totally stock engine.
You indicated in the first post you are running a larger cam and now you have changed to larger injectors. A tune is mandatory. You have to tell the PCM what size the injectors are, or excess fuel will destroy your engine. On the other hand, if all you did was cam, headers, throttle body you would have been fine with the stock 24 #/HR injectors. Still need a tune with the cam, to realize it's full potential.
You indicated in the first post you are running a larger cam and now you have changed to larger injectors. A tune is mandatory. You have to tell the PCM what size the injectors are, or excess fuel will destroy your engine. On the other hand, if all you did was cam, headers, throttle body you would have been fine with the stock 24 #/HR injectors. Still need a tune with the cam, to realize it's full potential.
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