Twin Turbo 33 pickup
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Twin Turbo 33 pickup Been awhile but I got my truck together enough to drive around about 50 miles or so. Its an all stock l33 , cam everything, has a holley hi ram intake though, 4l80e, 3.25 gear, 3200 ptc convertor and weighs 2950. I went to the track last Friday and it went 6.601@105.2. the 60' was 1.60. I was wondering about timing, at wot it is 13 degrees which I 'm sure is soft at 13 psi. looking for some tuning input for this thing. It's on e85 ,left just above idle and about 75-100 feet the boost started to come in and it spun pretty bad, got back in it and went the 6.601, coasted thru quarter at 12.42 @52 mph, How much timing is safe and still not hurt the power? just trying to figure this thing out as I go. It's really a street truck but wanting to see what I can get out of it. Thanks
Give it what it wants. Add one degree at a time until it stops going faster. I ran 13 or 14 degrees on my stock L33 on pump and water/meth. Added one degree and lost a bit of torque so I backed it off one degree.
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First sort out the suspension & tires so you can get good data from your passes. Then use mph for your bench mark for changes. Reading plugs is the best way to see what the engine wants. Yes, it's time consuming. But very accurate. The truck is very cool! A 6.60 spinning and pedaling is very good for a first pass. This thing has major potential tuned and turned up to 18-20psi.
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That's true on the suspension and tires, the tires were some we had left over from DragWeek . There is still so much to do yet , we pretty much stuck whatever we needed to last minute to get to the track. Probably the suspension will be the limiting factor as it is a street rod type. This is my first turbo build and having raced for years it's hard to not see if I can get a low low 6 out of it. I'm trying to get some of this laptop tuning sorted out or at least the very basic stuff. Thanks for the help, I appreciate it very much. Thanks Mark
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Don't sell the suspension short. Look up Dave Dennis' Model A on Mid Atlantic Street Outlaws. He does have a true 4 link in the rear, but it's a straight axle street rod front end. Does 5.80's on the motor and 5.10's on the bottle. Streetable at that! Your truck will look good with the front end about 6" off the ground at launch!
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Wow ,you are right, Dave Dennis model a is a beautiful and fast car. It gives me hope. With a little traction and tuning as you said I think we can get this thing a little closer to the 5s or very low 6s. Thanks
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I wouldn’t worry about total timing at this point... It’s the last thing to adjust. Since it didn’t explode at 13* I’d leave it there. Pop in a new plug right before a pass and read the mark on the heat strap. If it looks good leave peak timing alone. Add in your desired boost amount first at a known overly low “safe” timing level. Then square away AFR and power delivery. Last step is to slowly ramp timing and watch MPH and plugs.
What ECU/fuel management are you using? Trick is to progressively build power across the initial boost point over 1-3 seconds. If you just let boost come in hard and slap the tires it’s likely to spin. If you have a way to progressively pull/add power over time/speed you’ll get much better results. I couldn’t run more than 11lbs or so on the street with 29x12 slicks without blowing the tire off. I have a progressive boost/timing ramp now and I can run 20+lbs on the street with a 275 tire. Same power levels I run 8's with at the track.
No reason that combo can’t break into the 5’s pretty easy IMO. As mentioned, great looking truck!
What ECU/fuel management are you using? Trick is to progressively build power across the initial boost point over 1-3 seconds. If you just let boost come in hard and slap the tires it’s likely to spin. If you have a way to progressively pull/add power over time/speed you’ll get much better results. I couldn’t run more than 11lbs or so on the street with 29x12 slicks without blowing the tire off. I have a progressive boost/timing ramp now and I can run 20+lbs on the street with a 275 tire. Same power levels I run 8's with at the track.
No reason that combo can’t break into the 5’s pretty easy IMO. As mentioned, great looking truck!
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The ecu/fuel management is the Holley Terminator kit. The turbo stuff is all new to me this being the first try at this. I have a friend that has a turbo truck also and he is doing all the tuning at this point. he knows a lot more than I do ,we are just learning as we go. All the tracks are closed down around here now so I'm going to try to get a lot of stuff buttoned up over the winter. We built this as a street rod but now I gotta see if we can get this thing in the 5s come spring. It has the stock cam in it now and may get changed also. I really appreciate the replies and info, thanks again Mark
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One of the reasons for the timing question was a conversation with a racer that has set many records in true street and a few other classes and has tuned a lot of fast n/a cars , and turbo cars alike nand now has a super fast ls 427 vette. He was asking me about the timing on our truck and when I told him right now it was at 13* WOT. He said that the timing should be around 28* minimum and possibly as high as 36* depending on the tuning. I know basically nothing about this stuff as I have said but I cant see anyplace for that kind of timing on what I have. I'm really curious as to what the thoughts are. What this man has done over the last years on these cars can't be denied but man that seems different than what I'm seeing . Any thoughts? I'm not saying anybody is wrong or right but he is saying that there is a lot of power to be had . Thanks Mark
Yea that’s horrible information he is giving you for your specific application. You are not running an all-out race engine….the exact opposite actually.
I agree on high RPM race engines with large duration cams, big bores, and low back pressure race type turbo kits… you do generally run timing up where he is talking about. On SBE type builds with baby cams that will instantly break things… guaranteed. Ask your friend how many mild 5.3 turbo combos he has tuned that way.
Guys tuning SBE engines on the dyno, starting at 8* of timing. Get AFR square and then dial in the max boost. Then bump timing slowly watching power/plugs. Should see gains around 10-20whp per degree on most mild SBE setups. Many engines stop making decent gains at 11-12* on the stock cam. If you see only 3-5hp bumping to say 15*. That’s how you know the combo is done, and adding more timing is not beneficial. Back it back down to 12* and be done with it.
I agree on high RPM race engines with large duration cams, big bores, and low back pressure race type turbo kits… you do generally run timing up where he is talking about. On SBE type builds with baby cams that will instantly break things… guaranteed. Ask your friend how many mild 5.3 turbo combos he has tuned that way.
Guys tuning SBE engines on the dyno, starting at 8* of timing. Get AFR square and then dial in the max boost. Then bump timing slowly watching power/plugs. Should see gains around 10-20whp per degree on most mild SBE setups. Many engines stop making decent gains at 11-12* on the stock cam. If you see only 3-5hp bumping to say 15*. That’s how you know the combo is done, and adding more timing is not beneficial. Back it back down to 12* and be done with it.
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One of the reasons for the timing question was a conversation with a racer that has set many records in true street and a few other classes and has tuned a lot of fast n/a cars , and turbo cars alike nand now has a super fast ls 427 vette. He was asking me about the timing on our truck and when I told him right now it was at 13* WOT. He said that the timing should be around 28* minimum and possibly as high as 36* depending on the tuning. I know basically nothing about this stuff as I have said but I cant see anyplace for that kind of timing on what I have. I'm really curious as to what the thoughts are. What this man has done over the last years on these cars can't be denied but man that seems different than what I'm seeing . Any thoughts? I'm not saying anybody is wrong or right but he is saying that there is a lot of power to be had . Thanks Mark
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It is just not talk, he set several records in a few classes they were however about approximately 15 yrs back, the 08 z06 he has now is n/a and has been 5:89 and he drives it everywhere to race it. I would think he would be fairly well know. I'm very new to the turbo ls stuff and was just wondering about this. I will ask about his vette timing . I think he once said it was up in the high 30 but it is n/a and a different animal. I certainly don't want to cause a dispute with anybody over this , but looking for more knowledgeable tuning input. Thanks to all that replyed.
The fuel you run will have a large effect.The way I tune would prove what the engine wants. Simply dial timing back to something ridiculously safe like 8*. Get your AFR squared away and ramp up to your desired boost level watching plugs. Then add 1-2* until you stop making noticeable gains MPH or your plugs tell you you are too hot. Make nice easy consistent launches and watch MPH ignoring ET until you get it dialed in.
Tuning that way is always safe and if the engine wants 28* then it will be clearly seen in the MPH/plugs. (chances are it won't)
Tuning that way is always safe and if the engine wants 28* then it will be clearly seen in the MPH/plugs. (chances are it won't)
Last edited by Forcefed86; Nov 12, 2016 at 08:18 PM.
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X2 Forecfed is using the correct method for tuning. Please don't throw 28-36* at this thing. Nothing is more irritating than pulling down a fresh build for a rebuild/replacement. Ask me how I know. And it wasn't timing in my case. Just a leak. Love the truck and look forward to your first 5 second pass!