EPS Cam now Idles great--No more surging
09-29-2010, 09:31 AM
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EPS Cam now Idles great--No more surging I have an EPS cam 230/242/113 .600/.605 in a stock head Lq9. I have been having issues with surging and rolling idle as well as "cruise control" mode when driving along. I have had the car tuned by two tuners (within driving distance) already and neither could get it right. The car was tuned on a dyno and the WOT was dead on, just the issue with the idle. I decided to call Geoff at EPS to see what he suggested. He has always been more than willing to take the time to work with me as a customer. Seeing as he designed the cam, I figured he should have some idea on how to correct the problem. Long story short, I mailed him my PCM along with the list of my mods, he worked his magic and the car idles great now. No more surging and hunting when I come to a stop or when jockying in and out of parking spaces. He got this thing damn near dead nuts WITH OUT even seeing my car!!! It was definitely worth the money to me to have the car run the RIGHT way.
My only complaint is that his shop is TOO damn far from Chicago!
When I finally get around to building a "real" engine, I will definitely be giving EPS a call for my next build.
Brad
My only complaint is that his shop is TOO damn far from Chicago!
When I finally get around to building a "real" engine, I will definitely be giving EPS a call for my next build.
Brad
09-29-2010, 10:05 AM
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This idles better than my 383 with a 236/236 did when the car was a m6. It was tuned by a 3rd local tuner.
The one tuner has tuned my TR224 cam'd A4 gto as well as my 00 SS track ***** car and they are perfect. This particular set up just presented some issues.
09-30-2010, 01:23 AM
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I'm just wondering if those EPS cams are that much different that tuners will have trouble tuning them or getting the most out of them.
How does it feel power wise after EPS tuned it compared to the other tuners? You think it would put out better numbers now on the dyno or about the same, or was it just a matter of fixing the idle/surging problem?
How does it feel power wise after EPS tuned it compared to the other tuners? You think it would put out better numbers now on the dyno or about the same, or was it just a matter of fixing the idle/surging problem?
09-30-2010, 08:30 AM
#7
When it comes to tuning there are two major components.
1) WOT Fuel/Spark
2) Part Throttle
MOST shops can tune for this, and essentially make sure the car doesn't blow up. Which is essentialy for any guy with a lead foot that this needs to be done. When it comes to driving around and determining the "driveability" of the car almost every shop will tell you that this takes time and data needs to be logged in different driving conditions to determine what the car needs to have done. Weather, time of year, and other conditions can influence this. Not to mention the fact that the ODB2 pcm does not like when you mess with it and will like to make adjustments down the road to make things aggrivating. Most times cars need to have the initail tune, and 1-2 adjustments to get it pretty good driveability.
Some cams are easier then others but even easy cams back in the day, tuners needed to "learn" on them.
1) WOT Fuel/Spark
2) Part Throttle
MOST shops can tune for this, and essentially make sure the car doesn't blow up. Which is essentialy for any guy with a lead foot that this needs to be done. When it comes to driving around and determining the "driveability" of the car almost every shop will tell you that this takes time and data needs to be logged in different driving conditions to determine what the car needs to have done. Weather, time of year, and other conditions can influence this. Not to mention the fact that the ODB2 pcm does not like when you mess with it and will like to make adjustments down the road to make things aggrivating. Most times cars need to have the initail tune, and 1-2 adjustments to get it pretty good driveability.
Some cams are easier then others but even easy cams back in the day, tuners needed to "learn" on them.
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09-30-2010, 10:35 AM
#8
yeah... if your local tuners could not get that cam to idle, they were doing something wrong.
its not that hard to get a cam to idle...
get air fuel correct, and get it enough idle air, and pretty much it will idle. you dont even have to have the best spark value for it to idle...but you have to have fueling and idle air correct.
you need to get some better local tuners.
its not that hard to get a cam to idle...
get air fuel correct, and get it enough idle air, and pretty much it will idle. you dont even have to have the best spark value for it to idle...but you have to have fueling and idle air correct.
you need to get some better local tuners.
09-30-2010, 04:07 PM
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I agree with what you guys are saying.... WOT is easy. Both tunes were good on the WOT. I only picked up 3 rwhp on the 2nd tune based off of a back to back run with the first tune compared to the final one. I didn't expect to pick up anything anyway... drivability was bettter on tune 2 than tune 1. Tune 3 kept the WOT from tune 2 and corrected the drivability stuff. I went through the whole process on hptuners site and it did make it better. However, nobody was able to tell me how to lean it out at idle. I don't want to get into the whole tred again, but if I commanded 16:1 AFR while it was sitting there at idle, the portable wide band actually read closer to 14.7.
I don't think the EPS cams are any harder to tune than any other of the cams of similar or bigger sizes. The tuners just need to know how to tune for big cams.
I don't think the EPS cams are any harder to tune than any other of the cams of similar or bigger sizes. The tuners just need to know how to tune for big cams.
10-01-2010, 01:20 AM
#10
I agree with what you guys are saying.... WOT is easy. Both tunes were good on the WOT. I only picked up 3 rwhp on the 2nd tune based off of a back to back run with the first tune compared to the final one. I didn't expect to pick up anything anyway... drivability was bettter on tune 2 than tune 1. Tune 3 kept the WOT from tune 2 and corrected the drivability stuff. I went through the whole process on hptuners site and it did make it better. However, nobody was able to tell me how to lean it out at idle. I don't want to get into the whole tred again, but if I commanded 16:1 AFR while it was sitting there at idle, the portable wide band actually read closer to 14.7.
I don't think the EPS cams are any harder to tune than any other of the cams of similar or bigger sizes. The tuners just need to know how to tune for big cams.
I don't think the EPS cams are any harder to tune than any other of the cams of similar or bigger sizes. The tuners just need to know how to tune for big cams.
then after you have tuned the MAF you can set it back to the stock value of 4000 rpm, adn you can check the blend of the 2
after that you can go to idle airflow, which may require you to drill a second hole in the throttle body, you can only take the TB screw to around .55/.60 volts before it messes with idle parameters and never enters true idle.
personally I prefer to just drill the TB when you get to a 230+ cam, you will have to go there anyways at that point.
the idea is to get enough air at idle so that you get around 60 IAC counts when up to full operating temperate and the fans have been turned off and the AC is off..
you will want no more than +/- 16* in the over and underspeed tables
basically +/- 16* at 400 rpm away from idle and blend it back to 0* the closer to being at dead on 0 rpm different.
once you have those simple things done, it should idle without issues..
its not that hard to get a cam to idle in an LS based car...
if it is hard.. then you dont have one of the few things I listed above done correctly.
10-01-2010, 10:16 AM
#12
you obviously dont understand that on a cable drive car you cant go past .55/.60 without screwing other stuff up...Hard coded values in the pcm that will keep you from hitting idle conditions
ETC is a whole differnt story..no problems there...but there is still a limit of how far you can go...its just way higher and most people dont hit it...
you get into a 25x cam, I guarantee you have to drill some sort of hole for idle air for it to idle properly hot/cold/ac-off/ac-on
the biggest problem is that vehicles with an IAC arent designed to handl the extra air that is needed at a cold temperature with a cam... and they max out on what you can do without drilling at a fairly early point...
if our IAC motors had a larger available range, this would not be such an issue...
GM moving to an ETC style Throttle Body solves most of the problems.
Shame they didnt do it sooner.
ETC is a whole differnt story..no problems there...but there is still a limit of how far you can go...its just way higher and most people dont hit it...
you get into a 25x cam, I guarantee you have to drill some sort of hole for idle air for it to idle properly hot/cold/ac-off/ac-on
the biggest problem is that vehicles with an IAC arent designed to handl the extra air that is needed at a cold temperature with a cam... and they max out on what you can do without drilling at a fairly early point...
if our IAC motors had a larger available range, this would not be such an issue...
GM moving to an ETC style Throttle Body solves most of the problems.
Shame they didnt do it sooner.
10-01-2010, 03:40 PM
#15
OP, would you happen to have a copy of "Tune2" and "Tune3". I would love to see what he did. I should note that getting rid of bucking and surging from a big cam is MUCH harder to do with an M6 car. A stalled auto will usually absorb most of that.
10-02-2010, 08:15 AM
#17
There are alot of ways to skin the cat. Stock TB's have holes in them. Sometimes the aftermarket ones don't. You can only bypass so much air with the IAC and they are slow to react. Opening the set screw and zeroing out the TPS sometimes leads to other issues that prevent the idle routines from kicking in. So yes, sometimes you need to drill the TB blade.
10-02-2010, 11:38 AM
#18
I can make all of those cams Idle just fone without having to drill...
cold start, and AC on is a totally differnt story..
sitting still it might do ok... but returning to idle properly and smoothly and still keeping good off idle response is not going to happen with the limits of the TB Bump stop screw...its just not designed to do what you think it is doing.
if you have ever had to tune a carbed car you would have a better understanding of the differences you get by getting air thru an idle bleeder vs the job the IAC does.
and when the IAC reaches its limits because you dont have enough air gong thru to begin with, you get all kinds of idle issues and off idle response issues.
but you dont tune cars.. you take yours to somebody else...so you wouldnt know about tuning differences between the two.
