engine tuners
 

What do you guys tune for in a boosted application? I am familiar with my turbo drag car, but that's only 9seconds @ full throttle. What do most guys run in terms of boost vs timing vs afr? Im assuming less timing and more fuel, but wtf I'd like to hear some examples. I assume tuners are extremely conservative on their tunes by these (im sorry) gay numbers coming out of these bbc! Again, I have a drag car, BUT its got a 347ci sbf with a turbo producing somewhere around 8-900hp on 93 octane..

Run your 8-900hp 347 at redline for 30 minutes straight over and over and see how long it lasts.

well, lol, its a street car and its been together for over 5yrs.. ive havn't even changed the plugs.. so it runs well.. I am sure with better valves it would last pretty long..

Power doesnt kill parts(for the most part).. its rpm and detonation..

Oh, and please dont't take my OP as taking a shot at anyone.. I am honestly curious as to what people are doing in boosted situation because I am planning on twin turboing my bbc's in my formula ;)

800 to 900 horse power on a pump gas 347 is a stretch, but I didn't say anything. Doing it for 5 years on one set of plugs is complete bull****.

I do not believe you could own and operate such a vehicle and have so little knowledge of how engines work to wonder why the power output in boats is less than you would "expect" in a car.

This thread reeks of something fishy, most likely inexperience and lies.

LOL I tell you what.. ANY time you're feeling frisky, you just go ahead and fly yourself and your inexperience up here and I'll gladly show you:evilb::evilb::lolhit:

We dont know eachother, but I can assure you that I know more about how to make power then you do judging by your response.

There is nothing fishy. I am not an engine builder by no means. To be honest, Im a union ironworker by trade. Backyard mechanic by night lol

Ill go outside and take a picture of the powerplant that's a lie, just for you..

Could anyone share some actual data as to the tune required to make the motor's live under boosted conditions?

for Crossett lol Its an all forged 347, twisted wedge heads, solid roller cam, shaft mounted rockers, and that big snail is a gt4788.. http://i771.photobucket.com/albums/x...0503112106.jpg

I forgot, I did have the car on the dyno 3yrs ago and the tuner wanted a fresh set of plugs in it. Sorry, I forgot about that!

I have a turbo Mustang also. It is a self built, self tuned car. The HP is in the 500-600 range though.

The user community here is total different from the user community for any car I own. I have a turbo Audio A4, a turbo Mustang, and an International Scout. In each of those communities I could ask questions like, "what did you gap your rings to?", "how much timing are you running?", "what's your plug gap?", and I would get real answers. Here, I don't think many users could answer those questions about their boats. I guess when you are dealing with $10k cars you get a lot of guys that do their own work, but with $100k (and up) boats that just isn't the case.

I doubt you'll get answers to your questions.

Also in the past 15 years the user programmable ECU, the wideband O2 sensor, methanol kits and now E85; have been a complete revolution in street car performance. I just don't see that any of those have taken hold in the performance boating market.

Post your questions in the Tech Q&A section and you will get more detailed responses.

Most boosted engines are going to run around 30-32* of timing.

you want afr to be in the 11.5 - 12.0 range under boost and 12.5 - 12.8 NA. Timing will vary... 27-30 is about the max I'd go under boost

I appreciate your answers members! The afr of 11.5 is what my car is tuned to but I'm only running approx 20* of timing @15psi and max torque.. another 2-3* comes back in after that. Pretty conservative since the car is efi and I have an a/a ic(air to air innercooler).
On the boat I am planning on going with a/w ic and blow thru because of cost, simplicity, and efficiency. The blow thru setups alone cool the air charge to aid in avoiding detonation. And I know of several buddies motors with such that run up to 32-34* with approx 15psi as well. I am assuming the higher timing spoken about is with lower boost? Meaning like 5-7psi?
The egt's must be through the roof under sustained pulls with that kind of afr/timing right??

yes, 5-7 psi. EGTs in my boat are right around 1300.

no kiddn.. inconel valves right?

yes

The reality is you're not going to find much info since many are tuned by pros on a stand and then installed in the boat. Obviously there are issues with running WB O2 sensors with a wet exhaust, so you're not going to see many guys with a WB gage installed on their dash for them to monitor this data like we do in the auto performance world.

Keep in mind most marine engines take a lot more abuse and constant load than just about any auto engine, so they are generally detuned for longevity. So yes your 347 might last 5 years on the street, but chances are it wouldn't last for more than a matter or minutes or a couple hours if it was left running wide open in 5 gear... Which is why these big blocks are used and detuned. Your engine also lacks some torque thats needed in the marine enviroment. It's not that they can't make big power, many are cranked up and running big numbers, but they wont last 100's of hours like that without being torn down.

I'd have to look again at the dyno sheets, but I think the engines in my boat are tuned to around 10 psi, 11:1, and 32° or 34° timing... but I'd have to double check that. And yes, inconel valves.

That's the beautiful part about turbo's! My 347 made over 8xx rwtq @approx. 4800rpm with my t76 turbo kit. I dont doubt I'd have to detune my 347 to live @ wot. The biggest problem would be heat.

These timing numbers just shock the hell out of me! Are bbc heads better designed or require that much timing? That's N/A timing no?

On the topic of turbo marine motors, are they run as a dry exhaust manifold to the turbo and then the water injected into the exhaust after the turbo?

Does this create any issues with heat in the boat engine bay, as I assume one of the reasons we run wet manifolds on an NA marine motor is to control heat was there is next to no airflow through the engine bay (as opposed to a car..)

Thanks,

Craig

you can water jacket anything, its just time and money

I was just going to heat blanket the turbo, water jacket all others.

I would like to know how they tune in the boat, I want to put a smaller pully on my 540 procharged motor to make 7 lbs boost, but how do tuners know where to tune without monitoring exhaust gas? If they only tune on the stand how to they duplicate your header set up? the engines dynamics change with exhaust set up.
anybody have experiance with GT Performance in Upland Ca.?