race tune not working

[stangdriven]

hey man thanks for the support and lol that would be great but i live arizona lol ... but yea.. im not gonna stop til i figure out how to use the same larger maf with the tune

 

[LilRoush]

rob thats exactly my point... i shouldnt have to swap maf housings... and i run the pump gas til damn near empty before i put race in, then i tune, but being that supposedly the maf is to big... still doesnt make sense why it doesnt work, rob is right, why should i have to switch... im gonna try my stock housing and if it doesnt work, im gonna pissed... and of course talk to justin again and get it to where my bigger housing will work... otherwise what point is there to get a bigger housing for more power if i cant use a tune.... now i understand im not forced inducted, but that housing has proven gains on n/a v6 motors... and it could be the tune, but i noticed a gain after i put it on... but im gonna find out one way or another... didnt spend 60 bucks for nothin... i even specified bigger maf housing, i didnt specify what the size was, but justin told me use stock maf should be fine... its like well if the bigger works for pump why not for race, and why cant you tune it for race?????

I would say the issue is in the actual octane of the fuel when you switch. "near empty" isn't good enough. You need to drain the tank fully and run enough to clean out the lines prior to switching your tune to the new higher octane level. Even if the car runs out of gas, there is still unused fuel in the tank that is diluting the higher octane race fuel. Dropping just a couple of points will be enough to cause what you are seeing. It also accounts for the pump tune working and the race tune not running well.

 

[robb15033]

I'm no expert but my gut feeling is that running the gas down low and filling the tank with Racing Fuel would be just fine. If it wasn't high enough octane, that it would ping like hell before not running at all. Unless the engine has suffered a major loss of compression, then it would suffer with best case scenario's. Yes, No, ?? I don't know for sure. We'll see, I guess. I hope they can figure it out quickly!

 

[LilRoush]

When you jump from pump to actual race gas, little amounts matter a LOT. Even more so when it's being specifically tuned for a predetermined octane.

Say you run the car empty, and there's a gallon of gas in there. Then you add 10 gallons. You've diluted your high octane with 10% of the lower grade right from the start and the tune isn't going to run like it's meant to. If you just run it low, you have maybe 2 or 3 gallons left. Now you are getting into even more dilution, and lower octane than it's tuned for.

 

[robb15033]

Yep, I got ya.

 

[g36 monkey]

Which is exactly what I was suspect of. I'm glad lilroush is a genius

 

[stangdriven]

alright guys... i got my stock housing installed... the damn thing still doesnt do shit.... and i ran it to the point of being empty and put the race fuel in, no matter what happens to the octane with being diluted the thing should still run, it just may run like crap. but i do got ya on the whole keeping the octane level and not being diluted stuff.... but yea with the stock housing, my god did i notice the difference in loss of performance, put my bigger housing back on.. hello the performance is back... well idk what im going to do now... running my 93 pump tune and like 3 gallons of race gas.. i notice a lil bit of performance difference, increase mainly, which isnt going hurt anything so.. but yea... idk..

 

[stangdriven]

but next time im at the track if i can... im gonna run her down as low as i can go... keep on the pump tune... run the race fuel through and then get an extra 5 gallons of race gas and put it in once ive circulated through the other... and see... maybe thats my best bet... idk but im not exactly happy about this crap... i wont lie... i really cant wait til i get a aem ems so i can tune everything myself... that may be random lol

 

[LilRoush]

A larger MAF isn't really a 'power gain' type mod on the 3.8L - something here isn't adding up.

What is your full mod list?
When you say 'race gas' what octane are you getting?

Edit: Re-read 1st post and see it's tuned for 100 octane. Are you sure you're getting 100 octane and not something like C16? Also, the power gain from 93 to 100 isn't going to be that much unless you have an all out race built motor.

 

[g36 monkey]

I was wondering what his mods were as well. Lilroush has built a number of V6's, I built mine from a bare block and am now working on a second for my friends car.

You are in good hands, just help us help you

 

[robb15033]

As I suspected. A slight delusion of octane should never prevent the car from running. If it doesn't have mechanical compression issues than all you will get is knocking. VMP owes you a propper tune, explaination, and then some.. as long as you provided all the information needed.
Again, my new prognosis is this: I have a strong feeling that if you get this car dyno tuned, the two tune files that were working previously will not be up to par at all compared to the "real world" invariables put into the new tune files. The 3 tunes you will get from a reputable shop will blow away anything Justin has been trying to do for you.
If you ever want a second opinion to ease your mind, try giving a call to Excessive Motorsport in Manassas Va. They will help best they can over the phone. Please update! I'm very interested.

 

[LilRoush]

Just my $.02, but I have yet to see someone do a V6 tune better than Justin. I've seen his remote tunes do better than cars spending hours on a dyno by a lesser tuner.

 

[ttocs]

we are not sayin he is stupid, just that he has a very difficult job. I got a mail-order tune from bama and it worked long enough to get to the dyno and got a real tune. I had/have lifetime tunes from bama but unless you can do data logging and let them know what the motor is actually doing all he is making is an educated guess. Does he know you fuel pressure is up a litte? Does he know that the timing and everything else is set correctly? He has to trust you to tell him EVERYTHING he needs to know and that is just not as simple as it sounds.

You can keep dickin around with ordering the tune, changing this/that and see if it works - or you can go get a tune and also see if anything else is wrong. When he was done with my tune he said that the fuel injectors were running lean in higher rpms since the stock fuel pump could not fill the 24 lb injectors I put in. He also said that the ignition coil was probably starting to go out and I would be wise to pull it now before it strands me.

So the tune ended up costing me $250, but with that I got the insurance that I now KNOW it is set up right, as well as good info on what I should look into doing next. AFter a new fuel pump and msd coil the car is running stronger then ever as well as the drivability is much better. I have no problem coasting along at 1300 rpms and sounds mean as hell when ya get on it now.

 

[robb15033]

Just my $.02, but I have yet to see someone do a V6 tune better than Justin. I've seen his remote tunes do better than cars spending hours on a dyno by a lesser tuner.

He's great, don't get me wrong. I have read about some of his special projects outlined in magazine articles. I have read up on his history while with the SCT design department back in the day. I just think sometimes the impersonal way of acquiring tunes can be less efficient.
I went the way of a dyno tune and it worked out best. I know my dyno numbers out did Justins best by a bit comparing apples to apples mod-wise that VMP has posted. His whole business venture selling tunes is ingenious. It's a great thing he's doing in there in Florida. He's a madman! I love him.

 

[ttocs]

yea like I said I got a mail order tune but it was just barely drivable. I know some people have had them done and they worked great for them but I find it hard to believe that by using some educated guesses and praying that it would outscore a real dyno session. My motto is do it right, do it once.

 

[rz5.0]

73mm is not much bigger than stock. That is what the tune is for it should be able to measure the air coming in and conpesate. I would run the stock unit till it pegs unless FI.

 

[justinschmidt1]

That makes no sense.

Maybe im retarded but isnt a race gas tune just gonna run more timing?


I know all I do for my race tune is bump the timing a few degrees with 104 octane

 

[ttocs]

73mm is not much bigger than stock. That is what the tune is for it should be able to measure the air coming in and conpesate. I would run the stock unit till it pegs unless FI.

yes teh radius is only a littel bigger but remember how big teh measuing vain in the maf was. IT took up about a third of the space from what I rememvber

 

[rz5.0]

Really does not matter. Its not going to flow so much more than the stock. I bet its the tune. scott Your 90mm outflows both have any issues? I agree with justin.

 

[robb15033]

That makes no sense.

Maybe im retarded but isnt a race gas tune just gonna run more timing?


I know all I do for my race tune is bump the timing a few degrees with 104 octane

-Yes. This is exactly what I was told back when I first visited the shop. I am trying to learn a little myself. I have a long way to go but love tinkering with motors.