My DIY twin turbo build..

[dansauto]

This looks like a nice compact check valve..

45 NEW DELTROL 1/8" BRASS IN-LINE CHECK VALVES CMM10B1 - eBay (item 350363752898 end time Jun-16-10 18:38:43 PDT)

yep that should work good, I also used two pumps. I ran 3/8" drain line to the pumps then tee'd togather and ran back into the valve cover. I used .030 restrictors and (4) check valves. Once I did that I no oil problems. Note I ran the restrictors then check valve right at the turbo then another check right after the turbo. The pumps were mounted on the frame rails right where they get narrow above the skid plate under the car. I used the shurflow pumps but the ones you have should work fine.

 

[coupe]

I have a kit for installing twin turbos, exactly like a friends successful kit, and I am looking forward to the install. He used twin scavenge pumps and they work very well... 750 at the wheels in his 99 rt/10. He was "accidentaly" spinning the tires at over 100 mph on the highway...

Your friend wouldn't be Mike from DesMoines would it?

I went down the same path AndyMac is on now. One scavenge pump wasn't quite enough so we added a second. Also used residual pressure "check" valves above both turbos and backflow prevention valves after both turbos to keep them dry when the car was shut off. Turbos were dry as a bone and never one hint of smoke.

Double up the pumps, keep the oil from flowing into the turbos after shut down, and you should be good to go with twins like this.

For reference, here is when we had one pump mounted. Simply moved it over on the custom bracket and added another pump. Ran them off a relay that the fuel pump relay triggered. Always on when fuel pumps are on.

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[01_VENM]

NICE. looking forward to this completed project.

 

[AndyMac]

Thanks guys, I'm going to start rounding up some more parts.

 

[Phun70]

Your friend wouldn't be Mike from DesMoines would it?

I went down the same path AndyMac is on now. One scavenge pump wasn't quite enough so we added a second. Also used residual pressure "check" valves above both turbos and backflow prevention valves after both turbos to keep them dry when the car was shut off. Turbos were dry as a bone and never one hint of smoke.

Double up the pumps, keep the oil from flowing into the turbos after shut down, and you should be good to go with twins like this.

For reference, here is when we had one pump mounted. Simply moved it over on the custom bracket and added another pump. Ran them off a relay that the fuel pump relay triggered. Always on when fuel pumps are on.

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Yes, As a matter of fact it would be Mike from Des Moines!!

 

[AndyMac]

Well, good news for once. I spent about 30 hours in the garage in the last week and got my TT setup back on the car. (a lot of late nights) Thanks to you guys for your suggestions on optimizing my oiling system. So far, no smoke at any time.

So, for my oiling system, I took the sending unit out of the block and ran steel line under the car beside my oil pan where I then mounted the sending unit and check valved oil feed lines to the turbos. I used 1/4 line, and .63 restrictors at the turbo inlets. (I tapped the bottom of the fittings that screw into the turbos to accept carb jets to make changing restrictor sizes easy.)

For the return, I used 1/2" steel line to come down a few inches and then into 3/8 line to each return pump mounted on the frame. (lower than the turbos) I added a second pump as 1 pump will not handle both.. (at least not in my case) Out of the pump it goes right into a big check valve, and then into a 1/4" hydraulic line to each valve cover. I was a little concerned that the 1/4" line would not be sufficient, but under pressure, it seems to be enough so that it doesn't smoke.

The only thing left now is to get my injectors put in. They will require some modifications, but nothing too serious. I will post my results. I have been driving my car a bit, the stock injectors will handle a couple pounds of boost at 1/4 throttle, so I just need to not hammer down.

A few pics..

All cleaned for the car show

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AFR and EGT gauges along with my boost controller (which also doubles as my boost gauge ATM)

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Intercooler shot

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Later,

 

[BOTTLEFED]

lookin good


what fuel setup are you going with?

 

[Phun70]

That looks great, let us know the specifics when it's all done.

 

[AndyMac]

lookin good


what fuel setup are you going with?

Thanks.. For now, it's just the stock fuel system with some 60 lb side feed injectors. I do have a MSD BAP box as well.

I haven't decided on what to do long term. ie, dual or triple walbros in-tank, external big ass pump, etc.. I won't bother with it till the winter, but I am leaning towards the in-tank walbros.

Also considering water/****, but want to avoid it if I can. (I like it, but the less complicated the system, the better)

Later,

 

[Russ M]

Your fuel setup should depend on what your overall goal is. I can tell you that with the right tuning the booster pump setup like paxton uses can support about 800rwhp.

Its kind of a miracle really, the factory line has sections which are no bigger than -4 but with enough fuel pressure it will do the job.

 

[AndyMac]

That is amazing, is that just with stock injectors but 100+ psi fuel rail pressure?

Thanks,

 

[Russ M]

Thats with 52lb injectors running 120psi or so.

 

[AndyMac]

Thats with 52lb injectors running 120psi or so.

That is ********!

So, this afternoon I finished modifying my Nissan Maxima injectors and got them installed.

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Far right is one of my stock gen 1 injectors, middle is a Maxima injector with the connector shaved so that the factory Viper injector clips will fit on. Far left is a stock Maxima injector. For anyone who hasn't seen my injector thread, I filed the end caps off the Maxima injectors to increase the flow from 240cc to 550cc. (600cc in a Viper system)

I had to modify the tops of the injectors a touch and spread the injector hold down tabs to make it work. I used the stock Maxima upper injector O-rings and the Viper bottom O-rings.

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Then I scaled the injectors in my VEC to get it to start and run. It was pretty close, but I used this to fine tune the short term fuel trims.

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Took it out with a rough tune and it held 11:1 AFR and a rock solid 6.5 psi. I was a little concerned that the internal waste gates might not be adequate, but no problem.

The car feels good. I have a feeling the EBC is going to be a bad thing..

 

[sbarbier]

Nissan Maxima injectors? What??!! I go to a parts store looking for a temperature sending unit and told that they cannot even get one I would have to call the dealer. You rip some injectors from a Maxima and MacGyver them into a Viper! That's insane! I need more education on these toys.

 

[AndyMac]

So I put a fitting in the exhaust pre-turbo so I could measure back pressure today. I found that the back pressure to boost ratio is right around 2:1, even at 5500rpm. I did several pulls around 5-6psi and then a couple at 10 to 14psi. You typically want the ratio as low as possible, why still spooling the turbo in a timely fashion. 2:1 is acceptable, but getting to the upper limit.

Not saying these turbos are optimal, but they aren't as restrictive as some people have eluded to. I do think the power curve will peak early, but I do need to get to a dyno to check it out. I've tried using the HP calculator in the VEC logging software, but don't think the results are accurate.

Later,

 

[AndyMac]

Few vids of the car

Right click, save as..

Shot inside the car turning onto the highway, 6-8lbs boost.

http://www.myturboprojects.com/viper/media/low_boost_run_01.wmv

Shot of the tach.

http://www.myturboprojects.com/viper/media/low_boost_run_02.wmv

Later,

 

[AndyMac]

Been working on the car here and there the last few months. Built some manifolds to fit some GT45's and 60mm gates on the car.

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Here's the start of the 4" exhaust off the turbo.

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Gates are vented to atmosphere.

 

[jrod_okc]

ANY UPDATES?

 

[eucharistos]

good bump

 

[MARO-KEEN]

In for updates

 

[AndyMac]

I haven't done a whole lot the last few months, but I took next week off to finish the car up. I got some head gaskets and many assorted parts. I'll get some pics up as soon as I can.

 

[Darth Menace]

What was the final outcome to this project?

 

[AndyMac]

Wow, guess it has been a while since I've updated... Lets add a few more pics, I'll see if I can do it in chronological order...

So, I got rid of the T3/T4's and went with two 70mm turbos.

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Here is a pic with a "mock up" turbo, old turbo, and 60mm gate.

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My 4" "muffler" lol, if you wanna call it that.

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Pulled my heads to get rid of the paper gaskets. (They were still fine, but better get the MLS ones in there anyway.

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Stock heat shield back on and pipes wrapped. You can see I had to move my filters to under the car now.

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Monster exhaust wheel. (I like to think of it as traction control, or "boost by gear" lol)

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Exhaust done

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Tapped the block under the intake for a knock sensor. (for MSD Knock Alert)

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That about wraps up the winter of 2010/2011... More to come

 

[AndyMac]

So, last summer I spent fighting some issues where the car wouldn't pull past 4800 rpm. I blamed it on my smaller turbos, but it still exists with the larger units and massive wastegates. I hit the dyno late last fall anyway just to see, and only managed 700whp by 4800rpm where it would start going way lean no matter how much fuel I put to it. (still stock motor, stock valvetrain, etc)

So, I finally figured out it was weak valve springs causing my valves to float under high load and lots-o-boost. Valve float sends raw gas and lots of air into the exhaust which shows lean on my WB and why I couldn't richen it up any. (Tip - o2 and WB sensors only read air content, not fuel, so if there is unburnt fuel in the exhaust, it doesn't see it)

Anyway, so Valvetrain time.. Roes dual valve springs and locks.

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My home made valve spring compressor. To do this, you need to pressurize the cylinder so the valves don't fall down. You can see the line from my compression tester hooked to my compressor to keep the cylinder full of air.

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New Harland Sharp rockers and hardened pushrods.

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Also painted my intake and valve covers to something more appropriate.

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Added fittings to my intake and redesigned my fuel system slightly.

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Added a BAP

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New Acer tablet running win7 to tune with

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So that about wraps it up for winter 2011/2012.....

 

[AndyMac]

The car runs strong now, strong enough to shred gears doing a 3rd gear pull on the highway even though AFR's were 10:1 at the time...

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That is about it I guess, going to hit the dyno before fall to see what kind of power I can extract from the new setup. 800whp should be a joke on 91 with 800cc's of water/****. I kind of want to push my luck for 1k whp, but I don't want to trailer the car home from the dyno..

 

[coupe]

Good luck Andy. The car has come a long way. Engine bay looks great.

 

[AndyMac]

Thanks, I know it's not that pretty, but it gets the job done.

 

[AndyMac]

Just a little media for this thread. Kinda goofin around on my first run at the AutoX..

http://www.youtube.com/watch?v=UPjZyGCks6A

 

[7TH_SIGN]

Sounds mean! Excellent job and project!

 

[mach4444]

Agreed- sounds great! Thanks for the write up. you have an awesome car there!!