Hey guys I thought I would give you an update on how the Beltless Boost project is holding up after driving it around a bunch.

Well, Things seem to be just great. I've had a bunch of small things like plug connectors comming off ignition coils and IAT sensors dying on me, exhaust bolts rattling out, things like that that seem unrelated to the turbo kit.

I do have an oil leak at the oil drain gasket of the turbo. Its annoying and smells when it leaks and then vibrates onto the exhaust part of the turbo. But nothing too terrible has come from it. I should be fixing it shortly when I find some time. I just relocated to Michigan and currently without garage and its my only car as of right now so work time is pretty limited. I may have to change my name to MI_Vette now.

I'm running 8psi, up a little from the black spring of 6 psi. But I'm using a JoePMBC.com inline boost controller. It works great! Spool up is much quicker and I like it alot. Second gear will still kick the car sideways if you let it go through 3500rpm's (peak torque) or if you even think about shifting quickly from first to second at WOT. I have had it up to 12 psi and it was WAY to scary. I think the compressor starts to get into its efficiency range. Similar to what Chris has seen on his setup.

I'm planning on going to the track within the next few weeks if I can find some time. We'll see what it actually does. The same kit at 6psi on my Spare Buick Roadmaster Stationwagon engine with a big cam got a 12.5 @ 117mph with a slipping stock clutch. So the Stroker motor, the McLeod Twin, and the upped boost should bring the mph way up and the ET down quite a bit.

If you guys have any comments or questions lets hear them.

 

man I was wondering where the hell ya went... lol hadn't seen you on here for a while.. figured the move and all.


yeah like I said that turbo is just starting to get into its happy place when ya start letting it do its thing...

keep us posted on the results of the track.. mine is down right now.. motor is out and the new forged crankshaft arrived about an hour ago so tomorrow I will be making a trip to the machinist to have the rotating assembly rebalanced then reinstalling everything with a new set of clevite H series bearings.. the new crank is a nice piece.. Eagle with fillets and chamfered oiling holes. I hope it will balance out with no mallory, if it looks like it will require mallory I am going to order a set of new pistons and drop the compression down to around 8.0 : 1 to run some serious boost through it.

glad ya like that boost controller. I may go with a manual boost controller also, the greddy is cool for a few things like peak boost and start boost where it holds the gate shut but is kind of finicky about maintaining boost much above the stock spring pressure.. I would rather have a manual controller which I think would be easier to regulate how much I run.

anyways.. when ya gonna have a garage?



Chris

 

Sweet,
Im not the only one chasin down gremlins for some late year track time.
On the boost controllers, are you guys setting it up to feedback pressure to the topside of the Wastegate diaphragm? That's the only way Ive had any success with my profec B. I can't wait to run your guy's boost levels, Im thinking you should see some 135-140mph trapspeeds. If not more.

 

I'm just using a basic ball and spring mbc so it doesn't use the top port. For those fancy new fangled dual solenoid electronic boost controllers I think you need to. It uses the top side port to keep the thing forcefully closed so the back pressure in the pipes doesn't blow it open at all at high boost levels. And I'm guessing it helps from keeping the wastegate valve from slamming open and ripping the diaphram as well.

 

the reference line to the top port is to keep the valve closed.. even though a spring is rated at say 12psi.. it will begin to open slightly lower then 12psi which slows spool down.. the EBC's keep pressure to both sides so the spring remains neutral until the top port is vented to atmosphere through the solenoid and the spring can open the valve. this gives you much quicker spool time. the problem is adjusting the gain on the EBC to get the above spring pressure boost setting stable so it maintains and does not drop below or creep above the desired setting. so I will keep the EBC to net the benefits of the faster spool, but use a MBC to regulate the base setting higher then the spring rate..

the EBC can be set to keep the gate closed.. so If I put in 23psi, it will let boost onto the top side of the diapghram until it reaches 23psi then it opens.. with the gain turned way down it will just pulse the solenoid in broad pulse widths which won't matter much to the overall base setting of the spring. but I will dial in the MBC to the boost level I want in the end.. this way the EBC opens the gate where I want but the MBC is regulating the end result through leaking a little. obviously this requires two completely seperate reference lines off the intake manifold or the EBC would be getting the leaking source as well and would not be correct. follow?



thats tough I know and confusing.. but seems like it will be the most solid way to hold boost steady.

Chris

it will stay shut until it hits the setting I put in.

 

Now lets not forget the two types of manual boost controllers.

There's the leaky one, that basically bleeds off some of the reference boost to the wastegate so the wastegate will be seeing a smaller amount of boost than what is actually being produced.

The second type is a ball and spring. This mbc actuall holds off the boost reference from getting to the wastegate via a spring. The more tension you put on the spring the more boost it will take to push the ball out of the way and get boost to the wastegate. Once the boost pushes past the ball it goes to the wastegate and it responds quickly given the boost it now sees is now past what the spring is set at.

The ball and spring will not let the wastegate see boost until it hits the pre-set amount in the mbc. This helps ALOT with spool. I've used both types and the ball and spring one is by far better. And you can get them for about $45, not all that much compared to everything else I bought on my car.

 

good point.. for me I think with the two setup the leaky one will work the best and be the easiest to dial it in. the ball and spring one is pretty neat.. I only know what I read from the link but seems like a hell of good deal!!

Chris

 

The ball and spring set-ups are easy to build, and work pretty well. I built one for a turbo Buick about 3 weeks ago for about $6 worth of parts at home depot. The only thing I did notice was that I get about a 3-4 PSI spike over the desired setting. If I tighten the spring to achieve a constant 18 PSI, I get an intital spike to about 22 PSI, then it falls back to 18.

I am using a really stiff spring though, so that may be my problem. I was planning on trying a softer spring sometime down the road, or maybe a ball and spring style controller that wasn't built with Home Depot parts would work better, lol.

 

go go gadget power....lol.. I imagine you could use a lighter spring and get it to be more stable. probably just has some trouble getting past the initial opening.. have ya checked to see if the ball is getting jammed in its seat?

Chris

 

The buicks have the leaky style boost controller on them from the factory. I just took the grainger style one I built off and used the stock one, but with a new computer chip that sets the boost at an initial hit of 15 PSI, and then 17 PSI for the rest of the run.

I am thinking of going back to the grainger style though, spool up was a lot quicker it seemed. From a stop, it's not a big deal because I can just power brake until the boost comes on, but from a roll the car seemed a lot quicker with the grainger style valve.

I'm actually not using a ball, but an old N20 jet JB welded to the end of the spring. It's conical shape seals the chamber of the 'boost controller' perfectly. The hole in the jet is sealed with some excess JB weld. I agree that the pressure is struggling with the initial opening, and that a softer spring might solve the problem.

Either way, no worries man.