58mm throttle body
You will need to grind the ports from 54mm to 58mm. I did it by holding the 58mm gasket to the manifold, then scribed the 58mm outlines, then I stuffed some rags in my intake to keep chips out, and started grinding with a dremel. Took about an hour. Then I vacuumed the chips out while removing the rags. If you bolt it on without opening up the holes you will create bad turbulence going into the intake, and will probably actually lose a little power.
Lets say i do port the manifold to 58mm and get the throttle body will this effect my air/fuel ratio causing a problem because the engine is getting too much air? Especially is im still using the stock 24lb injectors?
Maybe on a full bore car not porting it will do something noticeable.I put my BBK 58 on recently and didn't port right now waiting to do heads ,cam and headers next springs and take intake off the car. I didn't notice anything at all in terms of big speed reduction. Car seems to run about same as before maybe a bit faster.I have a tazzo like a gtech to use for timing the car.
And the blades open normal,idle is fine..no bog if anything the car jumps too much off the line now but that might be as have my tps at around .78 and think its should be more like .50 to .65 or so.I will be tweaking the tps shortly ,its simple to do.
And the blades open normal,idle is fine..no bog if anything the car jumps too much off the line now but that might be as have my tps at around .78 and think its should be more like .50 to .65 or so.I will be tweaking the tps shortly ,its simple to do.
Originally Posted by C_Rules
Lets say i do port the manifold to 58mm and get the throttle body will this effect my air/fuel ratio causing a problem because the engine is getting too much air? Especially is im still using the stock 24lb injectors?
With an A4 car a TB requires programming unless you want to blow up the tranny, the more power it will give at less throttle can cause issues because tranny functions at TPS scaled this is even when the TB results in no gain of overall power as it would in a stock car. 10% throttle angle with a 58mm is a whole lot more air than it was at that same percent with a 48mm.
Is this an automatic car? If so you'll have to have the shift tables reflashed to compensate.
The reason is the trans shifts based on tps%,and since you'll get the same air at a lower throttle opening with a bigger tb, you get slower, sloppier shifts. It can kill the transmission.
This is even noticeable with a 52mm, but not as bad.
The reason is the trans shifts based on tps%,and since you'll get the same air at a lower throttle opening with a bigger tb, you get slower, sloppier shifts. It can kill the transmission.
This is even noticeable with a 52mm, but not as bad.
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You don't need to tune the throttle body and never heard of a throttle body swap blowing up an auto tranny and been messing with these cars a long long time. You do of course have to tune the car if you change injectors.
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Verdad Gallardo Wether reflashing is needed with a 52mm might be debatable but saying it isn't needed with a 58mm is flat out wrong. A shift kit, pcm shift firmess tweaks or a vacuum modulator can all take care of this real issue. The pcm tweaks can offer a lot more gains that the others as far as power and drivability so that is the most recommended course.
Looking at your mods I see a Granatelli which tells me you buy first and research later though so maybe that is the source of your mistaken info.
Looking at your mods I see a Granatelli which tells me you buy first and research later though so maybe that is the source of your mistaken info.
Originally Posted by C_Rules
If i get a 58mm throttle body for my LT1 do i have to do any mods to the manifold?
My 383" makes 508 at the wheels, through an unlocked 4400 rpm converter and 4.30 gears in a 12 bolt Moser, and it gained nothing. Unlike too much carburetor on an older car, a too-big tb won't slow you down, just cost money for no gain. If you have a 4L60E trans, like the others said, you will need the line pressure tables in the PCM shifted to maintain part throttle line pressure. Otherwise, good by clutches.Good luck, Ed
Last edited by Ed Wright; Oct 22, 2005 at 08:50 PM.
Originally Posted by Ed Wright
If you have a 4L60E trans, like the others said, you will need the line pressure tables in the PCM shifted to maintain part throttle line pressure. Otherwise, good by clutches.
Good luck, Ed
Good luck, Ed
I guess caprice and ed are the ones to go with. Only thing that sucks is that there are no LT1 tuners around here in NYC. Looks lke im gonna have to send the pcm to pcmtuneforless. Unless one of those power programmers will do the trick but im gonna have to read up them and find out what are all the things they can do. Also what size are the stock intake manifold openings?
DO NOT use a "power programmer" they cost more and do less than custom tuning you would be better off to drive down to pcmforless he is just over near Philly.
The stock intake openings are 54mm.
The stock intake openings are 54mm.
Originally Posted by LTSpeed
So if I go to a 54mm do I need to mess with the PCM? I have a 4L60E and you said you had to change it if you go to 58mm, but what about 54mm?
Good luck, Ed
Originally Posted by Ed Wright
If your car is as stock as indicated in your sig, you don't need a bigger throttle body at all. You will gain absolutly nothing. The stock MAF, throttle body & injectors are more than enough to support 400 hp at the wheels. There are much more productive places to spend your money.
Good luck, Ed
Good luck, Ed
im curious to know what should he spend his money on because im sort of in the same boat. i have my lt1 a4 bored out to 355, full exhaust, K&n fipk, trick flow intake elbow, msd ignition and no cats? im trying to go for an all motor car so what should my next upgrade be?
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Joined: Oct 2004
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From: Anna, OH
Originally Posted by Ed Wright
If your car is as stock as indicated in your sig, you don't need a bigger throttle body at all. You will gain absolutly nothing. The stock MAF, throttle body & injectors are more than enough to support 400 hp at the wheels. There are much more productive places to spend your money.
