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From naturally aspirated 225 to a boosted 170
https://www.slantsix.org/forum/viewtopic.php?t=66100		 Page 3 of 3
Author:  lgu32 [ Mon May 12, 2025 4:06 am ]
Post subject:  Re: From naturally aspirated 225 to a boosted 170
Few more tests. A bit faster pressure raising after the boost control table tuning. Boost pressures are generally higher now with new cam. Was 0,7 before cam replacement. Now 0,9. Full boost comes at around 4k and continues to red line with no restrictions. Over 4 really good power. Will go to track for tests at June.

Lazy launch could be partially reasoned because of Clifford intake with huge but short ports. I probably do a splitter in there make a dual plane. I testes it once with naturally aspirated 225 and got small gain. This modification it will be next winter stuff. As well I am going to change covernor weight lighter to get shifts close to 6 k at full throttle.

Happy me this doesnt leak oil from engine. Together with electric vacuum pump I have also a venturi in the tube before turbo for vacuum. The crankcase smoke goes to intake - cleaner environment.

Added subwoofer elements gave more bass for my music. These also cover well the valve train rattle.

Image
Author:  Dart270 [ Mon May 12, 2025 10:48 am ]
Post subject:  Re: From naturally aspirated 225 to a boosted 170
Sounds like nice progress overall! Cool trip from S to N too.

I found quite a bit of power increase going from 2.5" exh with more restrictive muffler to 3" exhaust with more open muffler. Not much difference down low, though. The turbo quiets the exhaust a lot, so a muffler may not be needed. I bet timing changes could help low end. Beyond that, a smaller turbo might be next...

Lou
Author:  Greg Ondayko [ Mon May 12, 2025 6:51 pm ]
Post subject:  Re: From naturally aspirated 225 to a boosted 170
Awesome trip. I bet the sights were fantastic as the days grow longer up north!
Author:  lgu32 [ Tue May 13, 2025 10:31 am ]
Post subject:  Re: From naturally aspirated 225 to a boosted 170
Yes. Days came longer but as well the temperature was decreasing all the time. Last 2 days were not so comfort. This was in north Germany. When I arrived and was garaging my bike (at Helsinki) it started snowing!

In the past we did trips to mid Europe with a Valiant. Of course with 225.

I did one launch test from parking area to highway. The boost comes slowly. 2800 rpm there was just 0.1 bar but at 4000 rpm close to 0.9. Easy launch as no tire spin. Sounded like I have raise my 6500 limiter as it could come before 1/4 mile trap.

Smaller turbo? This unit is sold for 2 liter four bangers. I think the Clifford manifold is my problem. Lets see if I made another efi manifold from a stock 1 bbl cast iron version. This is just a dream.

Just now I will drive and enjoy,
Author:  lgu32 [ Sat Jun 14, 2025 11:40 am ]
Post subject:  Re: From naturally aspirated 225 to a boosted 170
I was today at track for few test trials. I got my best with morning cold weather. There is still problem get boost at the launch. It comes with delay or if collected against stall this slips thru 1st gear.

My best was 14.8 seconds at 1/4 mile with trap speed of 163.5 km/h (101.6MPH). It was close to rpm limit of 6500 at trap.

The trap speed equals to 250hp which is about 200% over a stock 170 engine. I dont think I can get much more with stock internals. So it is better to stay where I am. 7.25” sure grip was fine and my 5 clutch disk modified 904 shifted nicely.

Next steps will be ”enjoying the car at city cruise”. I will not race this anymore but I will do some changes (like smaller turbo) for better traffic light launch (!).

Thas it!
Author:  Dart270 [ Sun Jun 15, 2025 1:57 pm ]
Post subject:  Re: From naturally aspirated 225 to a boosted 170
Congratulations! Sounds like great progress. Yes, best to enjoy it around town and make it livable...

Best, Lou
Author:  lgu32 [ Tue Dec 09, 2025 9:13 am ]
Post subject:  Re: From naturally aspirated 225 to a boosted 170
Image

Upgrade for season 2026. A Maxspeedingrods T3/4 turbo has been removed to get space for a Turbone HX30W (A Cummins diesel turbo!!!). The wastegate actuator from T3/4 has been moved to HX30.

The first trial around the garage building was promising… does make boost at lower rpm than the old one.

Both turbochargers are cheap ones from China.
Author:  Dart270 [ Tue Dec 09, 2025 11:43 am ]
Post subject:  Re: From naturally aspirated 225 to a boosted 170
Cool. Excited to hear more...
Lou
Author:  lgu32 [ Fri Mar 20, 2026 9:32 am ]
Post subject:  Re: From naturally aspirated 225 to a boosted 170
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HX30 clone did 0.5 bar at 3500. But I have do some porting for the wastegate as the max boost seem to be close to infinity. At 4200 I lift throttle because it was 1.15 bar (I have 0.7 bar spring at the actuator). I had to do the same for the previous T3/4 turbo. The max HX30 did at the road was 1.5 bar. I also lift there.

This HX30 feel like a good candidate for 170 engine.
Author:  lgu32 [ Sat Mar 21, 2026 10:50 am ]
Post subject:  Re: From naturally aspirated 225 to a boosted 170
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HX30 wastegate was 12.5mm and I drilled it to 16mm. After that I got max 1.1 bar boost (15-16PSI). 0-100km/h (0-62.5MPH) with ”D” gear uses 7.0 seconds. I like this better than T3/4 turbo which needed 1-2-D manual gearing to get the same seconds.
Author:  Dart270 [ Sun Mar 22, 2026 4:12 am ]
Post subject:  Re: From naturally aspirated 225 to a boosted 170
Wow, great results! Thanks for sharing.

Lou
Author:  lgu32 [ Fri Mar 27, 2026 10:39 am ]
Post subject:  Re: From naturally aspirated 225 to a boosted 170
I like the results too. I had a plan to replace the covernor weight to get shift rpm to the power range but as there is now well in the ”standard slantsix rpm area” I wont do it.

A thing I am doing later is a pushbutton set where I can choose the max speed available. This is because this is now dangerous - its really easy to get lost the drivers licence. It tested this close to my garage. There is not more than a bit over 100 meters from a traffic light to the garage port. And I did 0-100-0 in it! It is 40 km speed limit area and over 30 km speeding convert the driver a walker.
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