Drilling of a 1/8" hole in electronic throttle blade

[Force]

As the title says, my engine which is a cammed and blown Ly6 stroker and has an electronic throttle and an E40 ecm. We have idle pretty good now after a lot of adjusting RAF and timing. It has been suggested by a Pro tuner that we drill a hole in the throttle blade to get that percentage at idle back to around 18% instead of 24% like it is atm. This he says will give better control at idle. Can anyone here comment on their experience with this type of modification?
The cam shaft size is 226/[email protected]" .600 lift and 114Lsa if that helps. We have the idle pretty well nailed down but it does do a little hunt now and again under certain loads, but idle is basicly very good. I am running a fully manual T400 so the ecm does not know when it is in gear.
Any comments are greatly appreciated.

[07GTS]

i did have a hole in mine which was recommended when i have the cam/blower installed to help with idle ( can say the hole does make a big difference tho) now that i have hptuners i have plugged the hole and am tuning the idle properly it will take a bit but i can see it pretty much becoming quite good, just need to get the min air good and the adapt timing, i found that the adpt timing was always trying to correct the airflow so once the airflow is good the adpt timing dosnt have to do as much work, i also had to settle down the throttle follower torque table also around the idle area

[Force]

I have Hptuners and we have already tuned the hell out of idle. My question is is it worth putting a hole in the blade?

[07GTS]

all i can say is when i had the hole in there ( think it was 3mm ) idle was good just needed a little work, but then when i blocked it the idle turned to crap (surging) and needed alot of work so it does make a decent difference

[Force]

Thank you for the info. I am just trying to see if one of the senior tuners on here can comment as well. I am trying to see if tuning with the hole is better for controlling idle against not having it.
Did you end up putting the hole back in the blade? In your case it would seem to make sense.

[DSteck]

Don't do it. You should never drill an electronic throttle.

[Higgs Boson]

what is your spark timing at idle with the 24% throttle?

you might be able to raise it and get the throttle to lower.

[Force]

We have the base idle timing set at 26* and on the chart view in the scanner it varies from 19 to 26* roughly. I will put up my tune and a scan if I can match them up. I think dave has answered my question thanks Dave. It does not concern me if it idles at 24% throttle as it is idling probably as good as we will get it. It is dam good compared to what we had before the pro tuner played with it. It had hanging idle and that was a coastdown idle timing issue I think. It settles quickly to idle now and only very occasionally does a slight wobble. There is no hunting at cold start now either. There is no hot start issues either so I am happy. I am asking because the tuner who fixed the idle wants to drill a hole and have another play with it. Dave's advice will do me.

[Force]

dyno-final fuel fix sparkchange 8.hpt4.hpl


I hope this worked . It should be a matching tune and scan .
I haven't uploaded anything for a while. The 4.hpl at the end is the scan. The file ending in 8.hpt is the tune

[Force]

My scanner has filters on it for road tuning to get rid of decel fueling. The only other thing the engine does now and again is it dips slightly in revs when I pull up at idle to about 800rpm and then goes up again to 950 rpm where it should be. You can see it drop to 22% or 23% throttle sometimes and then goes back up to 24% instantly. It does not bother me but it would be better if it did not do it. The engine is putting out 760 hp at least so I am very happy with it.
The engine has cathedral Trickflow heads and is 404 cubes. Who wants to idle anyway lol

The tune is in open loop and we are leaving it in open loop for the time being. Should we use the 02 sensors and put it back into closed loop? We can apparently have the 02 sensors cutting out above certain rpms and map so it only works at cruise where you need it. Closed loop may be the next part of the tuning but I will consult my friend in Canada before going down that track.
Having a look at the base idle timing we did change the timing there as it was originally all 26* and now it is 12* then 26* . It was actually hanging on the 26* timing there and causing hanging idle on coastdown. I think the tuner may have played with the coastdown table as well, but I was not watching him.

[mowton]

I agree with the consensus that says don't drill. Cam isn't that radical (+4 overlap) and you should be able to tune the idle. Get LTIT/STIT set in all operating conditions and across full temp range (RussK). Get VE/MAF dialed in from 1200 and down in the idle area's. Use VCM controls for rpm control at the specific axis points if needed. Make sure cracker isn't overly agressive. Sometimes you have to bring in so much air for a cam to idle right at 0 mph, that the cracker actually adds more than is needed.

Idle timing should be about 2 to 3 degrees above stock. Again using VCM controls, push the idle timing around and find the lowest kPa (more vacum). when you reach that point and further changes have no effect, go back to that value, subtract 6 and that should be your base idle timing value.

It will take some time but you should be able to get it to behave pretty nice.

Ed M

[Force]

Thanks Ed

[DSteck]

E40, so you can't view the idle trims or desired value. :-/

[Eaglegoat]

I am declaring my self a professional tuner.

If people who think it's a good idea to drill a DBW TB are considered "pros", then I should be able to quit my day job shortly. I recently had a guy tell me that the shop and " tooner" that his car was at wanted to do the same thing. They said they were reading high IAC counts on his 2005 GTO. I also recently had a "pro tooner" tell me he'd never heard of tuning in open loop.

So once again, I am now a professional calibrator/tuner. I am now a guru! Spread the word.

[mowton]

E40, so you can't view the idle trims or desired value. :-/

Missed that :-(

Then here's to the longest running, active thread on the Forum :-)

http://www.hptuners.com/forum/showth...ling-down-idle

Ed M

[Force]

hahahaha , We are all glad that you think you are now a pro tuner. There is always more than one way to tune I suppose. I was after a proper opinion and that is why I ask the experts here. I know of one engine with an electronic TB and E38 ecm and it has a hole in the blade and idles fine. That is the only one I personally know of. I wont be doing it to mine.

[Force]

I have read 5 litre eaters thread and after the tuning we have done I have no hair left. lol

[THE CHAD]

Don't do it. You should never drill an electronic throttle.

I agree with DSteck never drill the blade on a DBW , ive seen it too often when performing retunes on Gen4's etc and with correct tuning you won't need and shouldn't resort to those wrong and drastic processes cheers Bret@ultimatelsxtuning

[Force]

Thank you for all your help cheers

[MikeOD]

Pro just means he charges money to tune...so sometimes I'm a pro and sometimes I'm an amateur (...I do it for free for friends, and I charge people I don't know LOL)...I've never drilled a hole in any TB. I've had to replace a few TB's/blades because of this in the past though when other people thought it was a good idea before the vehicle got to me for a tune. Can't even count how many times I've been "the third or fourth guy to try tuning this thing and it's never going to be right" only to fix nonsense like that and have the owners come back to me with all of their other cars they own to tune those too LOL.