timing with ethanol.

[dandaman]

Hi guys, I haven't posted much here but ive read an awful lot lol.

Wanted to pick the brains of some of the racers here.

We have a later model 3800 and are making 580rwhp@15psi using E98. Just looking for some advice on timing at peak torque and out the back. Its quite chunky at the moment up at 24deg most of the way through. Will raise boost and drop timng later but for now on 15psi what are you guys running with that sort of hp?

Cheers in advance

 

[dandaman]

53 views and nothing?

 

[Ttype6]

How high ar

We have a later model 3800 and are making 580rwhp@15psi using E98. Just looking for some advice on timing at peak torque and out the back. Its quite chunky at the moment up at 24deg most of the way through. Will raise boost and drop timng later but for now on 15psi what are you guys running with that sort of hp?

Cheers in advance

How high are you revving it? Is this rotating assembly completely stock?

 

[dandaman]

Forged H beams, Forged pistons, main studs, (later model has 4 bolt mains stock), balanced with ATI damper.
Using 2 Garrett GT3076R turbos.
Power slowly curls over at 6900rpm at 15psi, limiter set at 7500rpm.

 

[Ttype6]

Forged H beams, Forged pistons, main studs, (later model has 4 bolt mains stock), balanced with ATI damper.
Using 2 Garrett GT3076R turbos.
Power slowly curls over at 6900rpm at 15psi, limiter set at 7500rpm.

Does your set-up have four bolt mains? I run 24 degrees of advance on E85 with 28 lbs of boost up to 5,800 rpm.

 

[dandaman]

Does your set-up have four bolt mains? I run 24 degrees of advance on E85 with 28 lbs of boost up to 5,800 rpm.

Yes we have 4 Bolt mains. The later blocks have 4 bolt as standard. Were using the L67 block. What sort of power are you making at 28 lb boost? Any peppering on the plugs?

 

[MikeL.]

Ideally there should be a dark line on the ground strap of the plug and it should be close to where the strap starts to bend towards the threaded end of the plug. This line will move along the strap depending on boost and timing adjustments.

Where is yours located?

Ive always read leave timing on the low side 18 to 20 degrees, and up the boost to where you'd like it to be and only then start increasing the timing. Small adjustments in timing can have big impact on results and where that line moves along the strap.

 

[dandaman]

What do you mean "I've always read"? Are you giving me advice from a book or do you have personal experience? Sorry im not trying to be rude, its just there is a lot of bad info given out on the net. Im confident to tune im just looking at what other guys have done them selves personally. At the moment our plugs are clean with very little markings but we have not pushed it yet.

 

[Boost231]

good info mikeL, thats how we do it. keep timing low up boost to where we want it and slowly increase timing. ive never been one to go crazy with timing

 

[dandaman]

im going to get my plugs out when I get a chance and have a good look. What egt temp are you guys at?

 

[Boost231]

egts, where are you measuring? at downpipe? pre turbo? just after head?

 

[dandaman]

I have one in each runner just after the head. Averaging around 500f@WOT .

24* was as far as I was ever going to go really, its only because i'm on low boost at the moment that its up there. Though i've read in many pages guys running 25psi+ @24*.

Ill prob back it down to 20* and then wind boost up.

Just looking at what other guys are doing.

 

[Ttype6]

I have one in each runner just after the head. Averaging around 500f@WOT .

24* was as far as I was ever going to go really, its only because i'm on low boost at the moment that its up there. Though i've read in many pages guys running 25psi+ @24*.

Ill prob back it down to 20* and then wind boost up.

Just looking at what other guys are doing.

The only way to tell how much timing your motor likes is on a dyno or note mph at the track.

 

[MikeL.]

got this from racingone85.com, its a little lengthy but good info.

 

[dandaman]

like I said I know how to tune. I have a dyno and know mph at the track tells me where im at. I am just asking what other guys are doing numbers wise. last Sunday we went 140mph on 14psi in top gear as the glide lost low gear. Still managed a 10.90 but with a horrible 2.7 60ft. Box should be fixed this week. Maybe go out Sunday and have a bit more of a play. Should go into the 9s @14psi. Thanks for the link. ill have a look.

 

[MikeL.]

I've seen a 67 turbo on e85 run 10.20's-10.30's @ 132-135 on a 1.5x 60 at roughly 3500lbs timing fixed at 20* and boost 24-25lbs. Some have gone faster but this is one account I've seen first hand.

That trap speed is easy mid 9's.

 

[TT/Ameasap]

I've seen a 67 turbo on e85 run 10.20's-10.30's @ 132-135 on a 1.5x 60 at roughly 3500lbs timing fixed at 20* and boost 24-25lbs. Some have gone faster but this is one account I've seen first hand.

That trap speed is easy mid 9's.

Thats exactly what im trying to do. Still working out bugs with 93/alky, but have everything to convert...and I mean everything!lol. Currently at 21psi and she pulls hard with relatively low timing @ 20°.
Making switch to E85 next week or two.

 

[jdpolzin]

OP, I know you say you know how to tune but one key point of tuning that your missing is individuality. Each car is different, we all live at different elevations, we all drive in different temps and humidity levels. Is your car intercooled? What are you running for injector size? Is your fuel system capable of holding onto a steady duty cycle if you decided to bump up the boost? Personally, on your car, I'd start at 18 deg across the board and adjust boost accordingly to your cars capabilities as far as boost.We just tuned a hot air GN this past weekend and ended up at 19 deg across the board and 24.7 lbs of boost on a 4.1 with nicely ported GN1 heads. Car would get a small amount of retard at the 2-3 shift, which is common in our cars. When I say small, I'm talking less than a half degree. But, that shift point is where things tend to give on our cars so we kept adjusting from there with fuel until there was 100% no knock. Keep in mind, this is a hot air car with a big motor. When it comes to IC cars, there's a lot more on the table. I stopped 31 psi on a mid range turbo, basic build longblock, front mount, 21 deg with no knock on a car I built for a fellow member. This was on a single walboro, volt booster, hotwire, cold weather. I backed it down all the way to 22 psi 20deg when he came to pick the car up becuase he wasnt knowledgeable enough to tune at that point in time.

 

[dandaman]

I know all cars are individuals. I know elevation plays a part and air temp and pressure also. Is it so wrong that I ask for peoples ideas on what they have tried? Im not missing the point. Im meerly looking at what others are doing. Im using a vipec computer, id2000 injectors, pleanty of fuel flow (3 x bosch 044 pumps) etc. Large A2A intercooler Inlet temps at 14psi are 60deg f. Thanks for the info, ive set my timing @17deg for our 21psi springs we have for the gates. ill get into it slowly and add timing as we go.

 

[jdpolzin]

It's smart to ask opinions! Nobody is slamming u for it. Just trying to help bring some tuning ideas to the table to consider. Youll be ogood at that starting point. Keep us updated. Jeremy