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Turbo camshaft suggestions
https://slantsix.org/forum/viewtopic.php?t=66179		 Page 1 of 1
Author:  lgu32 [ Sat Sep 11, 2021 1:33 am ]
Post subject:  Turbo camshaft suggestions
I am building a 170 slant with turbo. I like to get camshaft suggestions.

- Cylinder head is ready for up to 0.50" lift
- Engine will be built to stock compression (8.5).
- Cast pistons because I dont know any forged available for 0.06" o/s.
- Power range shall be 3000-6500 (have a 3500 stall converter and 4.10 gears)
- E85 fuel only. Injected engine.
- Street and strip use. Idle quality is an issue. Idle can be 1000+

A custom grind is ok.

"Just which lobes I will ask from Oregon cams to my next build".

Please advise.
Author:  Joshie225 [ Sat Sep 11, 2021 9:22 am ]
Post subject:  Re: Turbo camshaft suggestions
A 170 wants less duration and a wider lobe separation angle than a 225. The fuel doesn't matter when it comes to valve timing, but the head flow does. That 3500 RPM stall converter will stall at a significantly lower speed with the 170 as you're missing 55 ci of torque and the higher velocity of the longer stroke. I'd probably use the OCG 818 on 112° lobe centerline, installed 6° advanced so you have enough torque to get the car off the line with some authority.
Author:  lgu32 [ Sat Sep 11, 2021 11:39 pm ]
Post subject:  Re: Turbo camshaft suggestions
What do you estimate for torque and hp peak power rpms with boost with that cam?

I am planning to use t3/4 turbo with its stock waste gate settings. It makes approximately 11 PSI then.

Internals are going to be balanced. Head with os valves comes from the current engine. Valvetrain is good for 6000+, tested.

EFI intake is built from Clifford (4bbl). Turbo exhaust is welded from stock manifold. No intercooler because E85.

Power band need to be go up to 6500.
Author:  Dart270 [ Sun Sep 12, 2021 4:33 am ]
Post subject:  Re: Turbo camshaft suggestions
Josh gives good advice there. I will take a look and think over the next few days and see if I can add more to this discussion. Ping this thread on Wed if I have not responded. Off racin', then will be catching up with work and family when I get back...

Best,
Lou
Author:  Joshie225 [ Sun Sep 12, 2021 10:18 am ]
Post subject:  Re: Turbo camshaft suggestions
I am going to revise my cam recommendation a little. Higher compression ratios make best power with wider lobe centerlines. Since this engine is 9:1 or less I would change the centerline angle from 112° to 110° with the same duration. Conveniently this is the Oregon 818 exactly as in their spec sheet.

My copy of DynoSim Advanced is from 2004. With the cam as specified the peak power is 5500 RPM. The parameters I used included a 1.7" intake valve and decent port work. 11 psi would bring the hp up to about 320. The power rolls off gradually and is the same at 6500 RPM as 4500 RPM. A 6500 RPM shift from 2nd to 3rd brackets this power range perfectly. The 1-2 shift will theoretically need to happen at a little higher RPM (6900 RPM) because of the greater ratio spread from 1-2 compared to 2-3. I don't know how tall a tire you run, but your top speed with a 26" tall tire, 4.10s and 6500 RPM is right about 120 MPH.
Author:  Charrlie_S [ Mon Sep 13, 2021 4:26 pm ]
Post subject:  Re: Turbo camshaft suggestions
Just a FYI on the 170 engine, in case you are not aware. Piston to valve clearance is critical with a milled head and after market cam, as the 170 is a zero deck motor. You might have to add valve notches to the pistons..
Author:  lgu32 [ Wed Sep 15, 2021 5:05 am ]
Post subject:  Re: Turbo camshaft suggestions
Quote:
Just a FYI on the 170 engine, in case you are not aware. Piston to valve clearance is critical with a milled head and after market cam, as the 170 is a zero deck motor. You might have to add valve notches to the pistons..
The head is "blueprinted". Milled but to stock dimensions. 54cc or something. As well the block is not even surfaced as the factory numbers are raised from casting. I think I am safe with that.

Our part store has Compcams "220" degrees cam in stock. This is bit more than grind "818 is with 212 degrees. Is it too much for 170?
Author:  Dart270 [ Wed Sep 15, 2021 8:14 am ]
Post subject:  Re: Turbo camshaft suggestions
What is the lobe separation angle for that Comp 220? That might work quite well for your 170.

I like the Oregon Cams 818 cam for the 170, but would ask them for 112 deg LSA or perhaps even 114 LSA. 110 seems to narrow for a 170 (oversquare), but might work better on a 225 (undersquare). The 818 is almost identical to the Mopar Performance 224/0.436" purple shaft cam I currently have in my 68 turbo Dart (225 engine). The Drake's Simca used this same cam (225) to go in the 9s in the 1/4 mile back in 2008 or so. That Mopar cam has a 108 LSA and I feel I'm losing something down low and would like to try 110 or 112 LSA on my 225 turbo. FYI, I have gone 12.75 @ 107.5 MPH in the 1/4 with this car, which weighs 3300 lbs going down the track.

To run up to 6500 RPM, I might use the Oregon 819 with a 114 LSA. You are dealing with a higher RPM range than a 225 engine. However, as Jush says, the 170 wants less duration than a 225 so maybe the 818 is better.

Happy designing, building, and testing!

Lou
Author:  DusterIdiot [ Wed Sep 15, 2021 4:54 pm ]
Post subject:  D
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Author:  lgu32 [ Sun Oct 10, 2021 10:18 am ]
Post subject:  Re: Turbo camshaft suggestions
This cam Ken is now grinding for my new 170 turbo engine.

Lobes are #2063 intake and the full recipe is:

224/224 @ .050", 256/256 adv, .440"/.440" lift, 110 sep

Otherwise the engine will be almost stock except os valves and light porting on head.

The turbo will be t3/4 style on the modified cast manifold.
Author:  Dart270 [ Mon Oct 11, 2021 8:00 am ]
Post subject:  Re: Turbo camshaft suggestions
Great. I'm sure you'll let us know how it works!

Lou
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