Isayimandrew's Twin Turbo Build

isayimandrew · 04-20-2022, 10:49 PM

Quote:

Originally Posted by Elmo370z

Be interesting to see your journey, as this method has everything negative going against you. Good luck, I hope this hold up.

I hope it does. I'm pretty much just going with Jotech's recommendations and they have some solid builds. I'm also not chasing a specific number and they know that so I don't think we will be pushing anything to the limits.

redondoaveb · 04-21-2022, 12:04 AM

Quote:

Originally Posted by Hotrodz

Stock block 750 plus and built motor 800 plus. There is a reason Seb only tunes to 700whp regardless of stock or built. The key is torque. Now you can dial the tq down to around around 500 tq at 700whp. When I was on a stock block w/stage 1 turbos I was at 600whp and 559tq. That said the smaller turbos spool much faster and the tq comes on fast.

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Hey Bob, I was talking about boost and head lift. Mine's making over 700 and probably around 530ft.lbs. but as you know, we went with the larger turbos so they spool slower and the torque doesn't hit so hard. That's at 15psi. 15 psi shouldn't have headlift issues and the OP wants to stay in the 600-650 range.

My point being. My car made 745 at a little less than 16 psi before we backed it off because stock block. The OP is using the Stage 1 turbos and won't be seeing 16 psi so I don't see him having any concern with headlift as Elmo was pointing out. He needs a stronger bottom end with those smaller turbos which he has.

My car could easily hit 800whp at less than 17 psi. If 17 psi isn't in headlift territory then I'd just build the bottom end too.

That's the reason I was asking what the threshold psi number is for headlift on the stock top end

Elmo370z · 04-21-2022, 08:02 AM

Quote:

Originally Posted by redondoaveb

What psi does the stock block start lifting heads?

You and bob are correct. It’s about torque. Cjm car never lifted head even over 50 plus passes and the drag strip. He ran 700-800+whp.

redondoaveb · 04-21-2022, 09:30 AM

Quote:

Originally Posted by Elmo370z

You and bob are correct. It’s about torque. Cjm car never lifted head even over 50 plus passes and the drag strip. He ran 700-800+whp.

At what psi does headlift become a concern?

Hotrodz · 04-21-2022, 09:37 AM

Quote:

Originally Posted by redondoaveb

Hey Bob, I was talking about boost and head lift. Mine's making over 700 and probably around 530ft.lbs. but as you know, we went with the larger turbos so they spool slower and the torque doesn't hit so hard. That's at 15psi. 15 psi shouldn't have headlift issues and the OP wants to stay in the 600-650 range.

My point being. My car made 745 at a little less than 16 psi before we backed it off because stock block. The OP is using the Stage 1 turbos and won't be seeing 16 psi so I don't see him having any concern with headlift as Elmo was pointing out. He needs a stronger bottom end with those smaller turbos which he has.

My car could easily hit 800whp at less than 17 psi. If 17 psi isn't in headlift territory then I'd just build the bottom end too.

That's the reason I was asking what the threshold psi number is for headlift on the stock top end

Copy that! PSI and compression ratio work together. If you are running stock block 11:1 you well need to achieve the same results as lower ratios such as 9:1. I am at 11:1 and 20.5 psi for 700whp and 607tq. Many start see head lift at 23psi and above. For a stock block with stage 1 turbos 14psi will get you just over 600whp and 500tq. Things will start to fail at 700whp on stage 1 turbos. It may not be head lift but the rods may decide to put windows in the motor.

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Hotrodz · 04-21-2022, 09:41 AM

Quote:

Originally Posted by redondoaveb

At what psi does headlift become a concern?

So about 17psi **** starts to go south on stock block with stage 1 turbos. You may not get head lift but you may!

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redondoaveb · 04-21-2022, 09:49 AM

Quote:

Originally Posted by Hotrodz

So about 17psi **** starts to go south on stock block with stage 1 turbos. You may not get head lift but you may!

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So with the power level the OP is wanting to achieve (600-650), headlift shouldn't be a concern, just the bottom end which he has built?

Building the bottom end isn't a huge expense. Doing Darton sleeves with fire rings adds a lot of cost to the build. If you're not planning on a high boost build, why incure that extra cost.

isayimandrew · 04-28-2022, 11:01 AM

Got worried after what Elmo370z and Hotrodz said so I double-checked with Jotech to see what they did to avoid head lift and the solution we went with is fire rings and the APR CA625+ head studs.

Just waiting on a few gaskets from Nissan and my motor should be finished up by the end of this week. Car is going up on the lift on Saturday to start all the installation!

Hotrodz · 04-28-2022, 11:19 AM

Quote:

Originally Posted by isayimandrew

Got worried after what Elmo370z and Hotrodz said so I double-checked with Jotech to see what they did to avoid head lift and the solution we went with is fire rings and the APR CA625+ head studs.

Just waiting on a few gaskets from Nissan and my motor should be finished up by the end of this week. Car is going up on the lift on Saturday to start all the installation!

You should be good to go! Looking forward to future updates!

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Elmo370z · 04-28-2022, 12:10 PM

Quote:

Originally Posted by isayimandrew

Got worried after what Elmo370z and Hotrodz said so I double-checked with Jotech to see what they did to avoid head lift and the solution we went with is fire rings and the APR CA625+ head studs.

Just waiting on a few gaskets from Nissan and my motor should be finished up by the end of this week. Car is going up on the lift on Saturday to start all the installation!

finally someone listened.

isayimandrew · 04-28-2022, 01:08 PM

Quote:

Originally Posted by Elmo370z

finally someone listened.

Definitely listening to the guys that have a lot of experience and knowledge on here. I remember when I first dropped it off Jotech mentioned solutions to mitigate head lift risks. I knew they did something and I trust them 110% with my build I just didn't know the details but it was good to come back and verify that they accounted for all of that similar to what you guys have recommended.

isayimandrew · 07-07-2022, 02:55 PM

Got more updates to share!

Motor is assembled

Turbo kit is installed on the motor

clutch and flywheel are installed

motor and transmission are back in the car

fueling system is installed

differential is installed in the case and ready to go on the car

Got a lot more parts to install but they're hoping we will be doing the professional break in for the motor and have it on the dyno by end of next week.

SR_GUY · 07-13-2022, 09:07 PM

Are you going to be driving this on the streets still? Hows the clutch and flywheel? A bit to aggressive for the streets? Just wondering because just got the same setup for my turbo build

Elmo370z · 07-14-2022, 12:09 AM

Quote:

Originally Posted by isayimandrew

Got more updates to share!

Motor is assembled

Turbo kit is installed on the motor

clutch and flywheel are installed

motor and transmission are back in the car

fueling system is installed

differential is installed in the case and ready to go on the car

Got a lot more parts to install but they're hoping we will be doing the professional break in for the motor and have it on the dyno by end of next week.

Do you have to retorque the heads bolts? I know with those 625 and copper after a proper warm up procedure it’s highly recommended to go back and re torque the head bolts.

isayimandrew · 07-14-2022, 08:51 AM

Quote:

Originally Posted by SR_GUY

Are you going to be driving this on the streets still? Hows the clutch and flywheel? A bit to aggressive for the streets? Just wondering because just got the same setup for my turbo build

Yes, this car will still be a street car. The car is still at Jotech so I don't know yet but i'll update you once I have it back and drive it around for a bit.

04-28-2022, 11:01 AM	#38 (permalink)
isayimandrew Enthusiast Member Join Date: Sep 2012 Location: Texas Posts: 310 Drives: 13 370Z Nismo MR M6 Rep Power: 12	Got worried after what Elmo370z and Hotrodz said so I double-checked with Jotech to see what they did to avoid head lift and the solution we went with is fire rings and the APR CA625+ head studs. Just waiting on a few gaskets from Nissan and my motor should be finished up by the end of this week. Car is going up on the lift on Saturday to start all the installation! JARblue, cv129, Hotrodz and 2 others like this.

07-07-2022, 02:55 PM	#42 (permalink)
isayimandrew Enthusiast Member Join Date: Sep 2012 Location: Texas Posts: 310 Drives: 13 370Z Nismo MR M6 Rep Power: 12	Got more updates to share! Motor is assembled Turbo kit is installed on the motor clutch and flywheel are installed motor and transmission are back in the car fueling system is installed differential is installed in the case and ready to go on the car Got a lot more parts to install but they're hoping we will be doing the professional break in for the motor and have it on the dyno by end of next week. JARblue, Rusty, Elmo370z and 4 others like this.

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07-13-2022, 09:07 PM	#43 (permalink)
SR_GUY Base Member Join Date: Apr 2016 Location: Georgia Posts: 23 Drives: 370z Rep Power: 8	Are you going to be driving this on the streets still? Hows the clutch and flywheel? A bit to aggressive for the streets? Just wondering because just got the same setup for my turbo build