Thumper

Without going with an external wastegate that is. 73turbo240z and I are having problems with boost creep. We are running the holset hy35w with an internal wastegate, megasquirt ecu, and a profec-b electronic boost controller. The turbo was designed for a 5.9l diesel running 18psi stock. We want it to run 12-18psi on a 2.8l. We have enlarged the internal wastegate hole twice its normal size and shortened the flap arm so that the flap opens further from the same amount of movement by the actuator. Any other tips either mechanical or tuning that might help us controll the boost creep? We would rather not have to upgrade to external wastegate. Any other thoughts? Thanks

All new cars are rated at the flywheel. Not 100% sure but on 70-74 z's they were rated at the rear wheels and then in 75 with the 280z they went to flywheel.

I've been to 158 with my old setup. It was rock solid. Adjustable struts, eibach springs, aftermarket sway bars, poly bushings all around, and w rated tires 160+ I beleive. I could have gone more but wasn't 100% sure how smooth the rest of the freeway was. Btw this was at 4 a.m. and I passed no cars and never even caught up to a car. Still not safe.

We want to keep our cars as street as possible. No race gas and no additivies. Our boost comes 15psi by 3200rpms by 3rd gear so it builds alot quicker. Also remember these are not race engines they are either a stock junkyard motor, or an engine that has been rebuilt with new pistons so nothing fancy smancy. I think i'm going to try these settings for awhile and see what happens.

Lol

When the tb is closed all that air hits a wall and reverberates backwards. It is strongest and most efficient to vent close to the tb. If you do by the turbo then it is weak and have already slowed down the turbo because the air is travelling backwards. So closer to the tb the better.

Oops Fixed!

http://videos.streetfire.net/video/0F155674-EE59-473E-9D37-3E92A2B64E7A.htm Watch out for the...

On z cars the afm is before the turbo so there is no pressure. So DO NOT install the bov any where before the turbo cause it just won't work right.

Supra one is not a great one but will work if you have no choice. Do not get a 2nd gen eclispe, talon bov. Your best oem bov is a 1st gen Bov off of a eclipse or talon. They can be had for $20 at a junkyard or $30-40 off of ebay. I ran one of those for awhile and it worked perfectly.

YES YOU NEED ONE. Its bad to run stock boost without a BOV let alone 15psi. You should put a BOV 4-6" before the TB. If you are running an afm you need to recirculate the bov into your intake tract. After the afm but before the turbo. If you do not recirculate it and let it vent to the atmosphere then your car will run really rich when you let off the throttle. If you are coming to a stop it might even stall.

You can get a cheap oil pressure gauge from any parts place and check your oil pressure. That way you know for a fact what is wrong. Also I would check your lifters like olie suggested. All you need to do is remove the 8 bolts on the valve cover and remove it. Good luck.

The car does not ping at 50+temperature up too 85 degrees. It hasn't been hotter yet. It only happens at cold cold weather. I pulled some timing and it should be much better. Megasquirt has a timing gauge on it so it tells us what the timing is at all times. I have verified the gauge is correct by revving the engine and watching the timing with my timing light so I know the timing is where it is suppose to be.

Congrats on the win. I hope this is the last you have to deal it. Btw $10, address, no questions asked Dirty deeds done dirt cheap.

Megasquirt only changes the fuel settings depending on IAT not timing.

On my stock turbo block 7.52:1 compression ratio I was running 33 degress at 140kpa and 30 degrees at 160kpa with never hearing detonation at all. And 73turbo240z on his 8.2:1 engine never heard detonation also intill it was 30 degrees out side. At 8-10psi level we are running 12:1-12.5:1 afr's. I think that to be on the safe side though I will pull 2 degrees more out of the map I posted at 140, 160, and 180kpa. At 20psi does 16 degrees look alright? Also if I do have a detonation problems up there what should be the lowest I put the timing 10degrees? Thanks

Z-GAD was those with your supra motor? stroker? or 2.8? Well here is my map after I tweaked it alittle bit. Mostly pulled some timing at 8-10psi. Btw 8psi = 155kpa, 12psi = 183kpa, 15psi = 203kpa, and 20psi = 238kpa

Ok took a look at the timing maps. At 8psi = 31 degrees, 15psi = 20 degrees and 20psi = 16 degrees. We haven't tuned the engine for 20+psi yet. I will post my timing map in alittle bit.

We are running the 280zx turbo distributor so no mechanical advance. We are running megasquirt with msd 6al boxes.

I'm not sure what timing is at 8psi but at 19psi it is 16 degres. And total timing is 39 degrees. I will have to look tom. I have another questions about total amount of timing I should pull. http://forums.hybridz.org/showthread.php?t=108246

Ok I have read different theory's but none reguarding non-crossflow 2 valve per cylinder engines. Right now my total timing is 39 degrees from 3500-6500. By 19psi it drops to 16 degrees so roughly 1.1 degrees per psi. This seems to fit most people theorys on how much to be pulled, but when I think of it as 16 degrees at 19psi that seems alot. Considering alot of cars stock timing is 10 degrees. So what do you guys think good timing or should I remove some more? How much timing pulled is too much? Thanks

Boost was at 8psi maybe creeped to 12psi nothing near what this engine can handle. I am going to pull a few more degrees out of timing just to be on the safe side though.

He is running 440cc injectors. And his block is made to handle alot of boost. But since he has a new clutch he has been running stock boost 8psi. I have tuned it to run 12.5:1 at 8psi and then at anything about 12psi the a/f ratios are around 12:1 then 11.5:1 at 18+psi. We never had a big problem intill it was 30 degrees out. I would think the IAT would adjust for the colder air going into the combustion chamber. But guess not.

From what you are describing bastaard it sounds like a very common problem on srt's. Especially if you have aftermarket intake or raise the boost. What you need to install is a catch can coming from your valve cover breather into your intake tube. The baffle plate inside the valve cover was not designed big enough so at high boost it tends to let oil seep through. This will cause your intercooler pipes to get oily, spark plugs to foul sooner, and black all over bumper. It is coverd many times on srt forums. You can buy polished ones for $90-100 or you can do-it-yourself for $20. When people install the catch cans they usually see about a teaspoon every week or two in there.