hp tuners eliminate shop tunes?

**griftymcgrift** · 02-06-2008, 09:48 AM

hey i know you guys have probably answered this like 10000 times, but if i get HP Tuners and tune my own car, do i ever have to go to a shop to get it done on a dyno, or can i just run off my A/F numbers and the like? i know i wont get HP or Tq numbers, but i was just wondering...thanks

**0rion** · 02-06-2008, 10:48 AM

no, you won't HAVE to go put the car on a dyno. It's probably a good idea to do it though. The difference is you can rent just dyno time and do the tuning yourself and save a bunch of money. I know the local guy here charges $100/hr for dyno time. I've never had my car on a dyno. I just dial in the afr and call it good. I'm probably leaving some hp on the table but I don't sweat it.

**MikeSomething** · 02-06-2008, 01:56 PM

Grifty, where at in NJ? I can recommend you to some places...

**Firebirdjones** · 02-06-2008, 05:13 PM

As Orion stated, you don't have to use the dyno to tune. Actually there are some people that would rather use the street as a more "real world" tuning device, with day to day driving. Takes longer this way, but some say it's better.

I have used dyno's but they are not the "do all" of tuning unfortunately. I can take the car straight to the track after extracting what is believed to be the most HP on a dyno,,,,,and still find that tweaking the tune is necessary at the track and on the street. Just went through this with my fathers car.

Thing is,,,,with DA changing everyday, there is no perfect tune for everything. If your looking for quickest ET's for the day,,,some tweaking will be required. Just how picky do you want to be????

What I like to do is get the car close on the street, and then just take it to the track,,,,make some passes, play with the tune and watch the MPH, keep notes and log everything. It's way more fun than a dyno session,,,and it's much cheaper to boot. When I feel I have the car as good as I can,,,I leave it at that. And as Orion said,,,,,call it good.

**Frost** · 02-07-2008, 06:01 AM

Originally Posted by Firebirdjones

..... I can take the car straight to the track after extracting what is believed to be the most HP on a dyno,,,,,and still find that tweaking the tune is necessary at the track and on the street. .....

You learn the tricks of the trade to make your dyno results line up with the real world though. The ONLY exception being some large laggy turbo's, and with a loading dyno, they are not an issue either.

**griftymcgrift** · 02-07-2008, 09:44 AM

im in south jersey....woodstown...vineland...theyre close to me. im not taking my car to the strip, so im looking for feel of the car. and i dont race ever so its all gonna be power under the curve. i just dont want to have to pay to use a dyno every time if i can do it myself and get similar results....and can i drive the car during the time i am tuing it ...like leave a stock tune while i play with the numbers? its my DD
thanks

**Firebirdjones** · 02-07-2008, 10:28 AM

Originally Posted by Frost

You learn the tricks of the trade to make your dynor esults line up with the real world though. THe ONLY exception being some large laggy turbo's,a nd with a loading dyno, they are not an issue either.

What I meant was with the DA changing everyday,,,,the dyno tune won't be perfect everytime. You may be able to fudge some numbers on these computer cars,,,I couldn't say,,,,but I go to the track quite often, depending on temp/humidity, DA numbers etc...I generally have to jet up or down 2-3 sizes. These aren't big changes, but as I was hinting at,,,it depends on how picky you want to get.

You can find a happy spot in the middle somewhere, and the car may only vary a couple tenths with weather conditions,,,and just call it good and leave it alone. But for my father it's not good enough, and we constantly tune the car at the track for conditions,,,,I told him to install a zipper on that thing,,,,lol.

As an example....

I used to run my 70 Formula in factory stock muscle car drags years ago, and I have a razor sharp tune on this thing to get a stocker to go as fast as possible,,,I can't count the passes this thing has seen over the last 20 years, but that Q-jet has had the lid off more times than I can count. I finally had the car to the point where DA only affected the car about a tenth in either direction so I left it alone at that point. After years of this,,,,I attended the Tri-Power nationals with the car and they had a portable chassis dyno on the premisis and for $60 you could make a few pulls with an AFR meter, I told my buddy lets do that just for giggles.

Now keeping in mind I had never had the AFR wideband meter on the car at this point. I tuned only from the track and watching MPH.
It layed down decent numbers for a stocker but what the operator was amazed with was the completely flat 13:1 AFR ratio all accross the RPM range. It was dead on,,,,car raced well that day too, went 5 rounds in competition and ET never varied more than .03 of a second.

Not bad for what some people consider a backyard tune. I tune customer cars this way all the time with good results. Although within the last few years I did invest in a wideband to make the process a little quicker,,,lol.

I have kicked around the idea of getting a chassis dyno with my wife,,,but I just haven't justified the cost factor yet in relation to customer base.

**Firebirdjones** · 02-07-2008, 10:37 AM

Originally Posted by griftymcgrift

im in south jersey....woodstown...vineland...theyre close to me. im not taking my car to the strip, so im looking for feel of the car. and i dont race ever so its all gonna be power under the curve. i just dont want to have to pay to use a dyno every time if i can do it myself and get similar results....and can i drive the car during the time i am tuing it ...like leave a stock tune while i play with the numbers? its my DD
thanks

If your not that serious about the car,,,then I wouldn't worry about dyno tuning. I'm not that serious with my 02 camaro either,,,,but I bought HPtuner so I could play with it. It's well worth the money,,,and I found 3 tenths a 3 mph with very little tinkering,,,just tuning on the street.

If you're not going to race, just looking for drivability,,,well it's up to you. I found HPtuner to be worth it's weight with more than just tuning. You can diagnose codes, scan functions,,,,,and yes you can do real time tuning while you drive,,,although I haven't figured that one out yet,,,,lol.

You can also scan any function of the car while you drive. That alone is worth the investment if you plan to keep the car.

Just the other day mine threw a check engine light. Without HPtuner I wouldn't have known what to do. Plugged in the laptop and found codes P0153 and P1153 which told me a slow responding and insufficient switching of the right side 02 sensor. So a pair of 02 sensors are going in tomorrow. Quick and easy fix that took about 5 minutes to diagnose in the garage.

If you plan to mod the car as money allows, a few things here and there,,,it's nice to be able to plug in the laptop and make the changes needed and your done. No scheduling appointments, no paying dyno time etc......
Just my thoughts on it,,,but it's really up to you and what you plan to do with the car.

**griftymcgrift** · 02-07-2008, 11:17 AM

firebird jones that is exactly the information i needed. your the man. im not that serious, just every time i mod my car i dont want to have to pay hundreds for tuning. im not looking for max power, just great drivability. im in a contest to win 250 and my taxes are coming for another 300 so thats what im getting...hp tuners...sweeeet

**Firebirdjones** · 02-07-2008, 11:30 AM

Originally Posted by griftymcgrift

firebird jones that is exactly the information i needed. your the man. im not that serious, just every time i mod my car i dont want to have to pay hundreds for tuning. im not looking for max power, just great drivability. im in a contest to win 250 and my taxes are coming for another 300 so thats what im getting...hp tuners...sweeeet

I appreciate the kind words, but keep in mind I am no expert when tuning on the laptop computer, I am still learning the ropes. Someone like Frost, Orion, Mrr23 have had more experience with it and could give you more insight on it.

If you are computer savy and know your way around a computer, then HPtuner will probably be a snap for you.

I myself have struggled to say the least, computers are hard for me, and a scary thought. But I jumped in knowing I was keeping the car,,,,and the thought of someone else punching buttons on it bothered me, not knowing what they were doing. The diagnostic features eventually is what turned the table for me. I decided I wanted to learn.

As a matter of fact,,,,,Mrr23 has done an extensive writeup on HPtuner,,,I don't know where the thread is,,,but a search should turn it up. With screen shots and explainations it really gives you an idea of what you will get into. Hope that helps.

**Frost** · 02-07-2008, 07:35 PM

Originally Posted by Firebirdjones

...What I meant was with the DA changing everyday,,,,the dyno tune won't be perfect everytime. You may be able to fudge some numbers on these computer cars,,,I couldn't say,,,,but I go to the track quite often, depending on temp/humidity, DA numbers etc...I generally have to jet up or down 2-3 sizes. These aren't big changes, but as I was hinting at,,,it depends on how picky you want to get......

This is a common misconception. A proper fueling calibration is just that; a calibration. Once the VE is dialed in against the MAP and if MAF, then the MAF is calibrated properly, temp and pressure are properly accounted for. Use the computer; that's what it's there for. I don't "fudge some numbers" and if you have, that is why you are not seeing consistent fueling.

**0rion** · 02-07-2008, 08:34 PM

what about the iat's input? I noticed this summer being OLSD there would be some swings depending on what the weather was doing so I attributed that to the iat sensor. That's about all it could be really. So what effect does the iat have when you're clmaf? I don't really see many tables that use the iat but it has to have some fueling effects at least while olsd.

**Firebirdjones** · 02-08-2008, 02:47 AM

Originally Posted by Frost

This is a common misconception. A proper fueling calibration is just that; a calibration. Once the VE is dialed in against the MAP and if MAF, then the MAF is calibrated properly, temp and pressure are properly accounted for. Use the computer; that's what it's there for. I don't "fudge some numbers" and if you have, that is why you are not seeing consistent fueling.

I understand what you are trying to say Frost, but it doesn't explain why I see so many computer controlled cars at the track adjusting fuel curves every time I'm there.

I know the computer is somewhat capable of adjusting the fuel up or down to a degree,,,,but I just don't think the computer is good enough for huge DA swings where it can be at or near sea level one day and then 4500 DA the next. I just don't see that happening....timing will have to be pulled out, as well as fuel,,,can the computer compensate for such a drastic change????

We can all agree that most people shoot for fuel trims + or - 4% and call it good. I don't think thats enough of a swing to compensate for large DA changes. With that said wouldn't it be safe to assume that if the fuel trims swing farther than that due to an unusual DA on this particular day then there is some fuel adjustment necessary to gain optimum times at the track????? Granted this would just be a temporary change,,,,,Maybe you are just that good with a computer, or my eyes are deceiving me, but I'm thinking the computer can only swing back and forth so far for small changes in DA. I am sure people that live in Colorado racing at 7,000 feet go about tuning there cars a little differently than those that live at sea level,,,,,NO???

No disrespect here,,,,Just tossing it out there, because I haven't had a car that would run the same at the track with DA all over the place, computer, carbed or otherwise.

**Frost** · 02-08-2008, 08:05 AM

The swings in trims (and to answer you and Orion both) are representative of error in the IAT/ECT biasing table being applied to VE from using the complex model for fueling. That bias table takes some serious number crunching to tune (Redhardsupra's MATLAB equations!) and thus part throttle trims wander opposite what one would expect (lean in summer and fat in winter) if the weather were ruling the change. None of this is any consequence to WOT fueling. If you have to play with WOT fueling and spark from track to track, you are not calibrating the PCM at all, merely tuning it to just get it right on the current day. There is a complete IAT spark table that is nearly empty from the factory except to pull timing under excessive IAT temps. It's true that you can run several more degrees of timing in cooler air, and once that table is setup you get it. When the MAF is properly calibrated as well as the underlying VE in high MAP areas WOT will remain consistent from place to place. If you have a tune with a butcherd IFR or other bad base injector tuning (a favorite among ls1 edit users since real tuning on VE and MAF is nearly impossible with auto tap) then you will certainly have fueling irregularities.

**0rion** · 02-08-2008, 09:11 AM

I'm with ya, that makes sense to me.

**Firebirdjones** · 02-08-2008, 09:43 AM

Okay that helps to understand things. Thanks for typing that out, not many people seem to want to go through the trouble.

Since I was referring to track tuning and wide open throttle, your comment makes sense playing with WOT fueling from track to track. Thanks again Frost.

**griftymcgrift** · 02-11-2008, 09:44 AM

hey i hope you know you cant get a more heplful group of people. sounds worth all of the 400 bucks. should i get a wideband too? and how does that work?

**0rion** · 02-11-2008, 10:55 AM

Originally Posted by griftymcgrift

hey i hope you know you cant get a more heplful group of people. sounds worth all of the 400 bucks. should i get a wideband too? and how does that work?

IMO the wideband should be required. Here's why. Why spend $650 on tuning software if you're just going to guestimate the tune? Because that's basically what you would be doing trying to tune with the narrowbands. Can you tune with narrowbands...... sure. Is it accurate.......not so much. With narrowbands you can get in the ballpark but that's about it. Do yourself a favor and spend the money on a wideband kit such as the LM-1 or LC-1 by Innovate. There are several good companies out there other than Innovate that make widebands, I just have experience with Innovate.