Fast VE table changes with more boost

[89 coupe]

I am currently helping tune a 347 Ford with FAST. This car had a XX Mondo Vortech blower and most of the VE numbers under boost were in the 100 range with good control of the mixture
We just installed a Procharger race blower. This blower puts out roughly twice the airflow of the XX trim.
This blower is rated at 3600 CFM max and the Vortech was rated at 1850 CFM max to give you an idea of the differences.
I know we will climb the VE chart much faster now than we were and we had a good tune with the previous blower. Do we just need to use approx the same numbers (around 100) to start with moved over in the chart or will the actual volumetric efficiency be way higher with the new blower and need numbers (around 150).
1. We are just looking for a good starting point with the new amount of airflow we will have and wonder if there is a formula available to help us achieve the results we are looking for in an efficient manner.
2. We want to be close enough on the first run not to hurt the motor by going real lean. (Most important)

Thanks
Martin

 

[cojo1]

fast

I just purchased a new fast system myself for my 89 coupe with a 347. I do not have that big of a blower on my car and will need help and learning the fast system myself. I was wanting to know if you tuned it your self or had someone in the Houston area you would recomend for tuning. Before I took out the stock electronics I was dynoed at around 500 to the rear wheels with a p1sc/ 10lbs of boost. I just installed a 355 pulley a hope for at least 12lds. Thanks, dulles18@yahoo.com

I have found that even though this is not a mustang site the people here are great when you need help!

 

[TurboJim]

I see you're in Tx. You have Jay Carter, Neal Whyte and Lawrence Conley down there. I dont know who you may be closer to, but they are all well versed on tuning and might be willing/able to help.

 

[NoSlix]

Martin,

To be safe, I'd increase the VE #'s 10% across the board. Then go from your torque peak up and increase another 10%. That'll put you in the ball park. FWIW, that XX trim moved more air than than 1850 cfm rating. It was more like 2000cfm in reality. Do short pulls or 330 foot passes to start with. If at any time you see it having to add fuel, go ahead and add that percentage all the way across the board from that map point all the way up and across to the right. Rinse, repeat. I seriously doubt you'll see VEs in the 150 range. Probably in the 120 range though once it's all said and done.

 

[Chyke]

You need to consider several items. Just because the blower (I am a Mustang guy at heart) is larger, doesn't mean it's going to make boost in the same manner. Nor does it mean that the motor will be able to utilize all of the additional air. Next what injectors are you running to have all VE numbers in the 100's under boost. I'm thinking you may want to step up the size of the injectors. Next find a dyno and start tuning at 1000 rpm intervals with a load on the system. With your blower, your boost is semi-linear with rpm (and load). It is easier to tune a blower car than a turbo car.

-Contact a reputable fuel injector service and discuss your injector needs.
-Once everthing is sorted out, get on the dyno
-I would recommend full telemetry, EGT, O2, Boost, Fuel press, etc.
-Load and run to 2000 than 3000 than 4000, etc.

Once you have a semi-comforatable tune start some full pulls. Be sure to monitor everything.

There is no easy answer for your question. You are changing a part which has major implications on your entire system (motor combo, gearing etc) Start from the begining so there are no un answerewd questions.

 

[NoSlix]

They've already got 160lb injectors. The car's been 8.40s at over 165mph. Fuel system wise, it's got it all and I don't think they're pullying it for a huge increase over what they're running now.

 

[Chyke]

Shane,
If one looks at this objectively, I don't recall the original post or any subsequent post identifiying injector size, or times for the car.
Infact if this is the case, the question is directed toward an inappropriate audience. One must bear in mind the relavance of knowledge when directing any communication, in expectation of a meaningful reply. One must also consider the ramifications of a reply should it be taken to heart. Many have blatant disrespect for others, I fortunately do not. Just offering my 10 cents cause my two cents is free...... Now carry on.

 

[NoSlix]

I happen to be old acquaintences of Martin and Alex(and the previous owner) so know a bit about the car in question. My replys were based upon my knowledge of the car that others may not have.

 

[89 coupe]

Just for an update we got a tune from another SSO racer and his VE numbers were in the 150 range. Alex played a little on the trans brake and the car responded much better with the larger numbers than with the old tune. He is coming over to review the datalog.

For a little info-
Actually I believe the injector's are 150's but we run a little higher base fuel pressure which works out the same as 160's.
We were maxing out the last fuel pumps and have installed a Weldon 2035 now.

 

[AEkrot]

Originally posted by NoSlix


I seriously doubt you'll see VEs in the 150 range. Probably in the 120 range though once it's all said and done.

Shane,

You are almost right on the money - I got the tune from Chris Derrick and it goes up to 121 VE! I remembered wrong and told Martin 150.

I ran it up on the brake and it did well up to 5500 rpm on the brake. I really need to get a better handle on the AE fuel stuff though. I had mine pretty close and thought I understood it. Then I looked at Chris' tune and it totally confused me (see my recent post about how AE MAP parameters - guess which settings are from Chris' tune...)

Thanks for the help! Are you going to make the Clash race in a couple weeks at River City (San Antonio?) I'll be there.

Alex

 

[JeffB]

Martin, another point that may help your understanding here is that the VE values are "ideal" VE numbers, not straight fueling constants (like the DFI and other systems use)... in other words, if your entire fuel map was set to a VE of 100, you would get twice as much fuel at 200kpa as you would at 100kpa... the FAST automatically adds extra fuel for extra pressure... so if you set your 200kpa VE numbers to be twice as high as your 100kpa numbers, then you'd actually get more like 4 times as much fuel at 200kpa as you would at 100kpa (because you're saying that the motor is twice as efficient AND the intake pressure is twice as high)...

as long as the new blower is pullied to make around the same boost as the old one, the only change should be the intake air temps (presumably one blower is more efficient than the other)... the FAST has built in air-temp corrections... so if the new blower is more efficient and actually puts out a much cooler, denser charge, then 15psi of its boost will have much more oxygen (per unit volume) than 15psi from the old blower... this may require you to bump the VE numbers to add more fuel at the same boost level... however, it may be taken care of automatically because the FAST will see the cooler air temp and know that the air is more dense... you could also try adjusting the ATS correction table instead of tweaking the VE... this would be a more theoretically correct way to do it since you haven't made any actual motor changes (ie. actual VE has not changed)...

 

[PTETURBO]

Sounds to me like the VE #s are way high. I would take a look at the injector duty cycle to see if it is matching your suspected Horsepower. You must keep in mind that the procharger might be sucking up about 450 hp from the crank. Depending on your camshaft the fuel consumption might also be high due to overlap.
Your combo will require at least 2 weldon 2035 pumps and 1 possibly 2 regulators. Your base fuel pressure will be about 65psi
and tell the FAST system you are using 180pph injectors. With this setup you should run between 70 and 80% injector duty cycle. Battery voltage is critical. I hope you are using a 16 volt system. The fuel pumps will love it. If you use a 12 volt sys and run below 13 volts the FAST will not be user friendly.

Just some ideas, I hope you can put them to good use.

Harry Hruska
Precision Turbo

 

[89 coupe]

Originally posted by PTETURBO
Sounds to me like the VE #s are way high. I would take a look at the injector duty cycle to see if it is matching your suspected Horsepower. You must keep in mind that the procharger might be sucking up about 450 hp from the crank. Depending on your camshaft the fuel consumption might also be high due to overlap.
Your combo will require at least 2 weldon 2035 pumps and 1 possibly 2 regulators. Your base fuel pressure will be about 65psi
and tell the FAST system you are using 180pph injectors. With this setup you should run between 70 and 80% injector duty cycle. Battery voltage is critical. I hope you are using a 16 volt system. The fuel pumps will love it. If you use a 12 volt sys and run below 13 volts the FAST will not be user friendly.

Just some ideas, I hope you can put them to good use.

Harry Hruska
Precision Turbo

I have to disagree on needing two 2035 pumps. I know of several people running just one of these at 1500 to 2000 hp forced induction motors.
I know one racer at the last Clash of the titans race running 8.30's with a Weldon 2025. This was a turbo car.
Alex's car used to have two Aeromotive pumps and we were on the edge but still had mixture control. The Fast system was adding over 10% at the end of the run. I understand that the 2025 puts out 40% more fuel than both the aeromotive pumps and the 2035 we have is rated even higher.
The alternator has been upgraded. We saw the problem's with low battery voltage.

 

[TD2593]

If you are concerned with fuel delivery and voltage I would suggest a belt driven pump. The new Aeromotive pump primes excellent and what I like best is the 0 voltage usage. With as much electronics as these cars have I say take advantage where you can. I second the 16 volt battery your car will love it. I have no issues with pump prime on my set up with the belt pump.

 

[AEkrot]

I wanted to go with the belt driven Aeromotive fuel pump. Cheaper, more fuel pump than I would ever need, no current pull on my electrical system, etc.

I opted for the single Weldon 2035 because it involved less changes to make it work on my car and the price was right. I was trying to make the change from the Vortech XX to ATI F3 in less than 4 weeks and be race ready.

I just got the blower belt where I think it will stay put. See pictures at the bottom of the below link if you want to see some before and after pictures of the car/blowers.

http://home.houston.rr.com/lt1corvette/

Like Martin, I too am surprised by Larry Hruska's advise that two 2035's would be necessary. Isn't the 2035 "supposed" to be enough pump to support 1800 hp? I'm anticipating ~1400 rwhp with the new combination. Add 400hp for the blower and that's about 1800 which is what the pump should handle. I guess if it runs a little short, I can go to a 16V system or the Aeromotive belt driven pump.

In any event, this post did generate a lot of helpful tips and suggestions. I appreciate everyone taking the time to reply to this post.

Alex

 

[Craig Smith]

-150 is too high of a number to have to put in for any reason other than a wrong one. This is most commonly caused by the injector flow rate you entered in C-Com not matching what the injectors actually flow. Some of these posts lead me to believe that not everyone here is exactly certain of what their injectors are rated at. Given that you all have a lot of time and money invested in your cars, may I humbly suggest that you send your injectors for flow testing if you are uncertain? Many tuning problems and questions can be eliminated this way. It isn't that expensive to have done and you can avoid a lot of problems and feel better knowing exactly what you have. Think of the money you've already spent - why skimp on this and continue guessing?

- It's not fair to compare fuel consumption on a supercharged car to anything else. If you have an engine that makes 1500 hp on the dyno and the blower takes 500 hp to run, you need to give it 2000 hp worth of fuel. So, for Alex's supercharged car which is estimated at 1400 rwhp, a single 1800 hp pump will not be sufficient. First, the pump's rating isn't for rwhp, it's for flywheel hp. So that 1400 is probably closer to 1600 or so. Add another 400-500 for the blower, and with your 1800 hp pump you are out of fuel before you shift. That 1800 hp rating is also at a lower BSFC rating than what a blower car will need to run at. Bottom line is get more pump. I second the notion that the Aeromotive belt pump would be the way to go. It's what I'll be doing myself.

 

[Chyke]

Thanks Craig. I said basically the same thing albeit symantics. Oh well, back to having fun. Know what ya got, or go home....