Guys - So what's the deciding factor in considering switching from MAF to SD? I'd like to make sure that my F1-R isn't being held back by tuning. Just wondering about the pros & cons between the 2.
Does SD yield that much more power in tuning or is it more useful for making our cars idle better while using larger injectors? Trying to decide whether to stay w/my current MAF system ( which is working just fine for me now ) or making the move to SD IF there's more power to be found there. BTW - what's the cost to change to SD??

Gene

 

Gene!

The MAF table can run out in certain applications!

Therefore the MAP sensor will enable you to tune it accross the board and take full advantage of the FI from start to finish!

It is more accurate to tune by Manifold Air Pressure on FI

Thanks,Matt

 

Matt - Sounds like U're pretty knowledgable about the MAP system so is there a certain brand that's better for our cars? Kinda looking for recommendations here!

G

 

ALL C5's currently have a MAP sensor. You are most likely running a 2 bar MAP.
Stock C5's run a 1 bar MAP.

 

Good Topic....Subscribing

 

I started running a 2 bar SD tune on my car a month or so ago. The car runs much better. I am very happy with the difference.

How much boost are you running? My car hits about 10lbs at 6300rpm. I was seeing my MAF maxing out at about 5500 rpm.

I paid about $100 for all the hardware needed for the switch over. You would also have to pay for someone to tune the car unless you do it yourself.

 

Congrats on the good results Mike Can you elaborate on how the car runs better ?...better throttle response-more power-???...any before/after dyno sheets?...just curious as I am contemplating the change also

 

IMO...best thing you can do is learn about tuning your car

Unfortunately , it does have an anti ....as in buying hpt or efi or whatever.

But at that point, you can remove the maf and sd tune your car.....it's worth the effort and can be very rewarding in the end.

When I first got my car, it was supposedly tuned by a reputable place.

For years, I drove it around and while it did seem to pull very well, only 3 yeears later, when I finally got down to checking things out, did I find out how much better it could run.

I bought the car with hpt, but didn't take the time to learn it and try things out...what a mistake.

When it was na, it idled like it had a BIG cam and idle quality changed from medium to rough at will.

It took about a week of fairly steep learning curve , but in the end, it ran much better...idle, t repsonse, overall power was better.

Then I tore it apart and slapped a blower on it...

I guess the point is that it does take a lot of time AND MOST of it is better done on the road.....so if you feel that you have it in you, I guarantee that you will love the results.

When i slapped a maggie on my car, I road tuned it sd to 10.8 afr, (was afraid to have it run lean). When I got to the dynio, their wideband was within a couple of tenths of mine....I did one pull at 547/521 at the wheels and left.


Think about it....no one will make it run as well as you can, with a bit of knowledge and some patience..especialy if you are going to keep your car and you want it dead on.

It's not ALL about peak numbers.... Idle , driveablility, t response, etc. all come into play. You don't drive it on the dyno, so get into the real world and tune it under the same conditions that you drive it under....on the road (if it's a street car).

JMHO



Another thought is to try and hook up with other vette people....1 software liecense can cover a model year or all models...C5 for example.

Then with someone riding shotgun, thngs are much easier to figure out and in the end, it's cheaper and better.

Real world example: I had hpt for my 03, then addd my 01 C5...recently, it cost me nothing to add another 01 Z06 and we went to a 2 bar sd tune....the owner noticed a BIG difference across the board.

 

Hey Buddy I'm with you on this one Recently I've PM'd/spoken with Rob (LuvmyC5) about tuning software & the learning curve associated with it. I have lotta stuff going on with home remodel & work now, just collecting facts for not-so-distant future

 

How much boost are you running? My car hits about 10lbs at 6300rpm. I was seeing my MAF maxing out at about 5500 rpm.

Mike - I'm running 14# right now but am thinking about going up to 17# ( especially if I upgrade to some better heads capable of handling the extra cylinder pressure - like the Dart's of RJW's!! ).
If ya can't tell by know I'm flying blind on this tuning method so are there any physical components to be changed out or is it simply a software upgrade?

G

 

2 bar can be done with a baro sensor out of a Cobalt....fits our cars kind of.

3 bar means old style map sensor and a short harness...or some wiring...connector is not te same.

Also, if you remove the maf, then a length of tubing to replace it and if iat sensor is in maf, then a gm style iat located somewhere else.

I think that is about it...along with software

 

Maxing out MAF or flowing more air than PCM's ability to read?...At what point do you need to go to 3 bar?

 

My MAF was maxing out due to airflow. It can only read so much, then it goes flat at the max flow number. The 2 bar is good to about 15lbs of boost.

As for the improvement; the car starts, idle better and seems to be more responsive. My dyno went from 532rwhp to 595rwhp with the SD tune and a cam from Andy. (with a rich 10.8 AFR)

As RJW said, best thing you can do is learn about tuning your car. Buying HP Tuner and a wideband was one of the best investments I've made. The learning curve is VERY steep. The guys on HP Tuner forum have really helped learning how to set things up.

It is feels great knowing I tuned the car

 

2 BAR can use the Supercharged Cobalt MAP. The pn is:12580698. I used this one, but I put two extra O-rings on it before installing it to make sure that it didn't leak. This should work to 14.7 psi of boost. You also have to trim off the ears on the left side to get it to fit.

Since you're thinking of going higher, you'd probably want to use this MAP: 12223861 I believe it's actually Officially a 2.5 BAR MAP, but I know that it's out of the 1989 Turbo Trans Am ( The Anniversary Edition that had the Buick GN motor in it).

When I went to the 2 BAR COS (Custom Operating System) using EfiLive, I had to redo the MAP scaling to show that it was reading the 2 BAR MAP sensor and some other stuff. I don't know too much about HP Tuners, but I know that it went relatively smoothly (In the words of the Beatles, " I got by with a little help from my friends......HOOOOOOO! Can't sing that song without the HOOOOOOO part!) and would highly recommend downloading the software and looking through it if you're thinking about doing it.

While you can tune using the MAF and GM operating system, the 2 BAR setup gives you MUCH MORE Accurate control over fueling and timing. My car feels quite a bit more responsive using the OLSD tuning that I'm trying now, but it might also be the 42 degree air too!

If you use either software, there is a pretty steep learning curve to them. I chose EfiLive because I could look through the software before buying it. I think that I made the right choice! Either one will get the job done! Maybe try talking to people, or visiting the different forums and get a feel for which one you're comfortable with.


After going over 14.7 psi.

1 BAR = Atmospheric pressure
2 BAR = Atmospheric + 14.7 psi
3 BAR = Atmospheric + 29.4 psi

The MAF is maxed out when airflow is over 512 grams/sec. This can happen in a hurry with boost. After this, then I'm pretty sure the PE table is used for fueling needs. If you take the MAF out of the picture (Speed Density), then the VE table (or in the case of a COS like I have, which uses a separate Boost VE table when the MAP senses boost/105 KPa) handles your fueling needs along with a couple of other tables. They use it as a system of checks and balances to make sure that everything is working as it should.

I just started tuning this year and while it's got a steep learning curve, it's also Very rewarding in that when I go WOT, and the car takes off, I know thatI helped do that! Of course the other side of the coin is, if it blows up, I know that I probably did that too! Just trying to give you both sides, so you get an idea what you might be getting yourself into!

Best of Luck!

 

A Big THANK YOU to Rob, Richard, and Mike Tuning is Definetely in my future, I will research as suggested then take a long thorough acclimation period of just using it to datalog before I even try to change my fan on-off temps I feel my car has at least a little more left in it safely as now I am only pushing 9.4 psi with 14* at 11.4:1 with Meth & 40oz Torco per tank of Shell 93. You guys will know what I'm planning before I do it

 

LuvmyC5/RJW:

Just curious as to your comments on the learning curve, I have a great tune (presently MAF), but will need to goto SD as I bump the boost up.

My tuner used HP Tuners, does having this base tune (works fine now -MAF) give me a good starting point to move to SD, or am I starting completly from scratch?

Gene - hope this adds to your thread


Nick

 

Guys - Here's an interesting read from our brethern over @ LS1Tech.com.

I didn't read all 7 pages but from what I DID scan over, it seems like the LS1 guys over there like the flexibility of the MAF system over the more precise tuning of SD. Ya'll can decide for yourselves.

http://www.ls1tech.com/forums/showthread.php?t=509481

 

 

You won't really be starting from scratch.... but it also depends on what the sd side of your tune is like at the moment.

Question: what happens if you unplug the maf????

If the car goes into reduced power mode, then no go, but if it doesn't, and all you get is codes but not reduced bs, then that would ive you a good idea of how well or badly the sd side o your current tune is...

Someone must be able to answer this question....also , I 'm sur ethat it has happened to more than a few over the years.

Just a thought

 

You're Very Welcome Scotty!

Don't be afraid to jump in and get your feet wet!Heck, I'm just starting to call myself a newbie at tuning! I'd say up to a month ago, I was a Newbie in trainig, but everyone has to start somewhere!

It's kind of like having that BEAST of a car of yours, in that you shouldn't be afraid of it, but you should Respect it because of the damage that it can do!

I've got more than a couple good books that I've reread a couple times now that tell what the different sensors do and basically how the computer thinks. If you understand what each sensor does and how they interact with each other, it'll help make your tuning experience easier. There are alot of good articles on the net too, but the bad part is that you have to decipher what's good info and what's not so good because the wrong info could make for a Very Expensive, Unpleasureable day! Caveat Emptor (Let the buyer beware)!

I just started tuning my car this year (and it seems like it's been forever), but have learned Alot by reading and asking questions. I've got TONS to still learn, but enjoy tuning, so it's not like work, it's like going to school and taking your favorite class! Once I got started, and over the overwhelming power of EfiLive, it became addicting! I'm Amazed with the stuff that this can do! Imagine if I knew what I was doing what could be done!

I'm not at a point to give you advice on whether or not you should start from scratch, but that's what I did except that I used the old tune's timing table, and the fuel except that I added 25% to it to make sure it wasn't lean. My advice again, read as much as you can from reptable sources and take it from there!

You can still run boost using the MAF. I believe LPE uses the MAF on the Big Power turbo cars. I believe that even if you are running the MAF, you should tune in SD first to get your VE first to get your fueling tables in order and then if you put the MAF back in service, when you max it out, you know that your fuel will be right! Like I said, I'm new to this and if I'm wrong, I hope that someone corrects me (I'm pretty sure that I'm not wrong though).

Sorry that I couldn't help more! Good Luck!