alamantia

iTrader: (10)

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?

ShevrolayZ28

iTrader: (4)

thats shade tree at best. have it properly tuned. lots of places in your area that can do it right.

Bill'sWS6

iTrader: (6)

Worked well for me..... I never had any issues with idle after drilled it out a bit. Don't remember what size I used?

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,

alamantia

iTrader: (10)

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.

Mart00SS

iTrader: (19)

Some people say yes drill the hole, some say no, but without a doubt a good tuner can make the car run perfect without drilling a hole in the tb. Whats the LSA on your cam?

alamantia

iTrader: (10)

230/224-111 with brand new bone stock 234 heads. Rest of the motor is stock aside from headers

white2001formula

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

alamantia

iTrader: (10)

I will have it tuned before I futz with it then

mark21742

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

Pharcyde50

iTrader: (11)

With a correct tune you shouldn't need to drill. These cars are pretty easy to tune. I got mine running great with HPT pro and a lc-1.

Paint_It_Black

iTrader: (1)

Nothing wrong with a small hole in the throttle blade to help out with a big cam. And it won't cost you $500 or more for the tune.

soundengineer

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

Paint_It_Black

iTrader: (1)

Exactly.. it's not always a tune problem, sometimes it's an "the engine needs more air to idle with all the gasses spitting back up into the intake from the overlap of the big cams" problem.

02*C5

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.

soundengineer

iTrader: (16)

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.

ShevrolayZ28

iTrader: (4)

Another way is to adjust the set screw so the throttle blade opens a tiny bit more. Then re-zero the TPS.

soundengineer

iTrader: (16)

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...

ShevrolayZ28

iTrader: (4)

Ok I was just kinda throwing that out there lol.

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.

soundengineer

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...

SF 1HOTLS1

iTrader: (24)

back from the dead...but when is it necessary to drill two holes? My cams in the 257,264 .646/.646 range.