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View Full Version : my high idling bored out 58mm TB



jaydog82
12-04-2009, 04:46 PM
Ok so i bored out my Throttle Body to 58mm and used a TB plate from a 91 camry v6. i blocked off the idle air control valve and closed the manual idle adjustment screw, but my car still idles at 1,500-2,000 rpm. does anybody have any ideas how i can lower my idle, i think the air that is slipping by the butterfly plat is raising the idle.

85gtsblackman
12-05-2009, 03:22 AM
tighter fitting butterfly plate :shrug:

jaydog82
12-05-2009, 04:24 PM
that is what i was afraid of. i am going to have to find something to fix this problem

METDeath
12-05-2009, 06:11 PM
My thought would be to take a stock TB to a machine shop and take the plate you want and ask them to make the TB big enough for the plate, they'll have high precision equipment to be able to do it right. Now, you could help them a bit by getting it close to the size of the plate, but still under the plate all around so that they can make the fitment exact. However, I'd rather just take them a stock TB.

85gtsblackman
12-06-2009, 05:48 AM
buy 2 stock tb, one to use for now, the other for the machine shop


or buy 1 stock tb, and take your fabbed one to a machine shop n tell em u want it bored to 60mm and cut u a tb plate to match


if it were me i hate to say buy id just have tried a v6 camry tb

jaydog82
12-06-2009, 08:08 AM
i did it would take custom work to get it to mount up.

85gtsblackman
12-06-2009, 09:04 AM
tb swaps are usally easier if done in the other idea i had

reference sake

for instace the camry v6 and some other tb's are 60mm

take an extra 5s intake manifold and lop off the flange to the stock tb

take the imzfe manifold and lop off the flange and keep tb

go get 1mzfe flange welded to 5s manifold or get some cast aluminum and some bolts, take to a machine shop and have them weld custom flange so camry tb bolts on

Lonestag
12-06-2009, 10:08 PM
I have seen a lot of people have little bugs when the up-size their TB. Has anyone noticed any real HP gains from putting a larger TB on?

Just curious.

Freshnicity
12-06-2009, 10:34 PM
I have seen a lot of people have little bugs when the up-size their TB. Has anyone noticed any real HP gains from putting a larger TB on?

Just curious.

Same question here.

I could how it would allow air to flow through the intake tract less restrictively, but not sure how it would affect AFRs on the stock ECU

rizin
12-07-2009, 12:28 AM
With the new TB where where does the power seem to drop off?

jaydog82
12-09-2009, 06:12 PM
so apparently what the honda guys do to fix leaking TB plates is to put a thin bead of sealant on the TB wall before the plate to stop the air from leaking past the plate. so far it works. i don't know how much more hp i will get, but i have heard from other people who have done this mod is that it pulls all the way to red line instead of dropping off.

i will keep you all posted.

joe's gt
12-09-2009, 09:25 PM
I'd imagine more of the restriction comes from the plenum than the actual TB opening. Just speculation tho.

91stxcelica
12-10-2009, 12:18 AM
had my throttlebody bored by maxbore.com and had no problems with idle.

jaydog82
12-10-2009, 03:43 PM
you have to port match the intake also and it helps to open the runners

Hookecho
12-15-2009, 04:08 PM
you can port match but you won't be able to enlarge the runners.

BiscutWheels
12-16-2009, 12:31 AM
I have seen a lot of people have little bugs when the up-size their TB. Has anyone noticed any real HP gains from putting a larger TB on?

Just curious.


Yes. bolt on gains are minimal, 4-6whp depending on what else is already done. I like to run a 7M-GTE TB, much larger than that (~62mm) is just too big and all that happens is a way touchy throttle.

Nate

jaydog82
12-17-2009, 07:23 PM
i am hopping that by having a larger TB my car will keep pulling all the way to redline instead of dieing off.

BiscutWheels
12-18-2009, 01:18 AM
it will surely help. There is a size at which one sees diminishing returns (no more power gain). That size is about 62mm for a general factory engine.

Nate

91stxcelica
12-18-2009, 09:28 PM
All I noticed was quicker throttle response, car seemed to rev easier. Thats with bored TB and port matched intake manifold. possible HP increase but never dynoed.