Drill Throttle plate to achieve good idle with aftermarket cam?
#1
TECH Fanatic
Thread Starter
iTrader: (10)
Join Date: Apr 2006
Location: NJ
Posts: 1,320
Likes: 0
Received 0 Likes
on
0 Posts
Drill Throttle plate to achieve good idle with aftermarket cam?
Put a TR230 in my car, has lots of power and runs good but idle is a little crappy, hard to start too. I heard of drilling the hole in the throttle plate a little bigger. Is that true? What diameter is it now 3/16? What should I make it for a TR230?
#3
11 Second Club
iTrader: (6)
Join Date: Jun 2004
Location: Ann Arbor, MI
Posts: 419
Likes: 0
Received 0 Likes
on
0 Posts
A tune is always the best way to handle this. I had mine tuned but still had some idle issues and drilling a bigger hole worked for me.
If you do drill it make sure no shavings get into the intake.
Good Luck,
#4
TECH Fanatic
Thread Starter
iTrader: (10)
Join Date: Apr 2006
Location: NJ
Posts: 1,320
Likes: 0
Received 0 Likes
on
0 Posts
While the car was apart I sent the PCM out for a mail order tune so when everything was back together it would be in the ballpark. I suppose a true dyno tune is in the plans for the future, i am still not convinced that a tune will 100% solve it.
As shade tree as it may seem to ream the hole. The current hole diameter was calculated for the stock cam so it would only be fitting that a different cam would have a different diameter hole.
As shade tree as it may seem to ream the hole. The current hole diameter was calculated for the stock cam so it would only be fitting that a different cam would have a different diameter hole.
#7
TECH Apprentice
iTrader: (5)
Honestly, I think a tune is better.
I drilled my TB and moved the set screw out years ago. Finally got tired of trying to get it perfect, so I pushed the set screw back in, got a replacement OEM TB plate, and tuned it out. I'm much happier now.
Don't drill, find a good tuner, or learn how to do it yourself. I didn't find it very hard once I understood the concept. I was using an LS1 Edit version from 2002 as well.
-Chris
I drilled my TB and moved the set screw out years ago. Finally got tired of trying to get it perfect, so I pushed the set screw back in, got a replacement OEM TB plate, and tuned it out. I'm much happier now.
Don't drill, find a good tuner, or learn how to do it yourself. I didn't find it very hard once I understood the concept. I was using an LS1 Edit version from 2002 as well.
-Chris
While the car was apart I sent the PCM out for a mail order tune so when everything was back together it would be in the ballpark. I suppose a true dyno tune is in the plans for the future, i am still not convinced that a tune will 100% solve it.
As shade tree as it may seem to ream the hole. The current hole diameter was calculated for the stock cam so it would only be fitting that a different cam would have a different diameter hole.
As shade tree as it may seem to ream the hole. The current hole diameter was calculated for the stock cam so it would only be fitting that a different cam would have a different diameter hole.
Trending Topics
#9
Tighten your throttle closed stop bolt in alittle to hold the blade opened some more...I think its a 7/32" allen head.
After that, unplug your TPS sensor and turn the key, wait a minute, turn key off and plug the sensor back in. Turn the key on again and your TPS will be reset to 0 at this position.
1st, try giving it about a 3/4 turn tight, that should get you there
After that, unplug your TPS sensor and turn the key, wait a minute, turn key off and plug the sensor back in. Turn the key on again and your TPS will be reset to 0 at this position.
1st, try giving it about a 3/4 turn tight, that should get you there
#12
8 Second Club
iTrader: (16)
Drilling is totally dependent on the Cam and the type of Throttle Body you have
if you have a drive by cable Throttle body, then drilling s the best way
if you have an Electronic throttle body, then you can get away with it in the tune...though drilling still winds up more stable most of the time
the basic principle is like that of an idle bleeder on a carburator.
the car needs more air to idle properly
we have an IAC motor... that on a stock vehicle, is open to approximately 60~80 steps at full hot operating tempertures at idle...
if you have an ETC vehicle then this is represented by the TB Blade being opened more instead of the IAC motor
while its not necessary to have it this low with a cam, it sure is useful...
if you cam requires more air at idle, then the IAC has to open up further.
if your cam requires more air than your IAC can open, then it wont idle properly regardless of how you tune it.
if you look at the IAC counts when the car is at temp and at idle and its really high...then you have no room for the IAC to compensate...
drill the hole, get the IAC counts to a more reasonable level(back in the 60~80ish range) and suddenly you can tune the idle easier.
some cams can get away with just playing with the tune...other cams you are gonna have to drill the TB blade
I have attached a spreadsheet I use to determine the hole size to make when I choose to drill a TB blade out
if you have a drive by cable Throttle body, then drilling s the best way
if you have an Electronic throttle body, then you can get away with it in the tune...though drilling still winds up more stable most of the time
the basic principle is like that of an idle bleeder on a carburator.
the car needs more air to idle properly
we have an IAC motor... that on a stock vehicle, is open to approximately 60~80 steps at full hot operating tempertures at idle...
if you have an ETC vehicle then this is represented by the TB Blade being opened more instead of the IAC motor
while its not necessary to have it this low with a cam, it sure is useful...
if you cam requires more air at idle, then the IAC has to open up further.
if your cam requires more air than your IAC can open, then it wont idle properly regardless of how you tune it.
if you look at the IAC counts when the car is at temp and at idle and its really high...then you have no room for the IAC to compensate...
drill the hole, get the IAC counts to a more reasonable level(back in the 60~80ish range) and suddenly you can tune the idle easier.
some cams can get away with just playing with the tune...other cams you are gonna have to drill the TB blade
I have attached a spreadsheet I use to determine the hole size to make when I choose to drill a TB blade out
#14
TECH Fanatic
iTrader: (1)
I had my car tuned by probably the number 2 tuner in AZ. The guy has a proven track record in builds, H/C combos and tuning. We had to finally put a hole in my TB blade last week and idling has become a lot better. I will say that it is a no return point though once you do it the only way to fix it is to get a new TB. So make sure your tune is spot on and if nothing else can be done to help idle then drill a hole.
#15
8 Second Club
iTrader: (16)
I had my car tuned by probably the number 2 tuner in AZ. The guy has a proven track record in builds, H/C combos and tuning. We had to finally put a hole in my TB blade last week and idling has become a lot better. I will say that it is a no return point though once you do it the only way to fix it is to get a new TB. So make sure your tune is spot on and if nothing else can be done to help idle then drill a hole.
incorrect... you can always have the blade filled... you get a real high temp soldering iron(not a radio shack special) or a torch made for soldering plumbing together(thats the easiest way) and some silver solder and flux...you can fill in almost any hole and it will be structurally sound.
#18
TECH Addict
iTrader: (4)
only on a smaller cam...and you can throw other things out of whack in the pcm with that...even if you reset the position to 0...
and a lot of cams you have to open it so far that it sets a code in the pcm and messes up a lot of stuff...
many tables reference TPS...
and a lot of cams you have to open it so far that it sets a code in the pcm and messes up a lot of stuff...
many tables reference TPS...
At any rate, should the cam he has be all that hard to get to idle? It's not exactly the monster donkey dick size.
#19
8 Second Club
iTrader: (16)
no...tr230's are pretty easy to get to idle...
27-32* of spark at idle(have to play with it...its been a while since I've tuned one of that one) get AFR good at 14.68ish at idle....
and then get the idle airflow correct..
determine after you get it up to operating temps if you need a hole or not..look at IAC and see where it sits... if its up in the 120-180 range... you need a hole.
once you have a hole you can redo idle airflow...
27-32* of spark at idle(have to play with it...its been a while since I've tuned one of that one) get AFR good at 14.68ish at idle....
and then get the idle airflow correct..
determine after you get it up to operating temps if you need a hole or not..look at IAC and see where it sits... if its up in the 120-180 range... you need a hole.
once you have a hole you can redo idle airflow...
#20
no...tr230's are pretty easy to get to idle...
27-32* of spark at idle(have to play with it...its been a while since I've tuned one of that one) get AFR good at 14.68ish at idle....
and then get the idle airflow correct..
determine after you get it up to operating temps if you need a hole or not..look at IAC and see where it sits... if its up in the 120-180 range... you need a hole.
once you have a hole you can redo idle airflow...
27-32* of spark at idle(have to play with it...its been a while since I've tuned one of that one) get AFR good at 14.68ish at idle....
and then get the idle airflow correct..
determine after you get it up to operating temps if you need a hole or not..look at IAC and see where it sits... if its up in the 120-180 range... you need a hole.
once you have a hole you can redo idle airflow...