Project Thread sc400 with M90 and water/air intercooler

[JustenGT8]

I am a little concerned about the rear runners though. Because the air is being forced directly at them, I wonder what effect that my have on the amount of air that gets to the cyl. Might want to be a little lean. Thinking about a baffle maybe.

what you guys think?

yeah same concern as expressed earlier...good to hear baffle helped

RE BOV...mine just had the single port on top of the diaphram

 

[SuperRunner]

here is what it looks like with the hood on.

 

[stevechumo]

Wow! You should name your M90 a rocket propeller.

 

[SuperRunner]

So I took the car out for a spin last night, after having to replace the starter last minute:17:

Anway, car doesn't seem to be making any boost, but I don't know for sure. Could have boost leak, or my belt is slipping. I don't have the front of the supercharger bolted down yet(wanted to wait make sure belt alignment was proper) so it definatly could be slipping....or there is something else wrong.

Question is, when should I see positive boost and how much? Not really sure how superchargers are designed to run. Should I see MAX boost at say 2,000 RPM when I flash the converter? I can hear my bypass valve(greddy BOV) opening when the throttle is completely closed, and pretty sure it is staying closed. Losts of little stuff still unfinished, and will start tying up all the loose ends next week.

 

[stevechumo]

So I took the car out for a spin last night, after having to replace the starter last minute:17:

Anway, car doesn't seem to be making any boost, but I don't know for sure. Could have boost leak, or my belt is slipping. I don't have the front of the supercharger bolted down yet(wanted to wait make sure belt alignment was proper) so it definatly could be slipping....or there is something else wrong.

Question is, when should I see positive boost and how much? Not really sure how superchargers are designed to run. Should I see MAX boost at say 2,000 RPM when I flash the converter? I can hear my bypass valve(greddy BOV) opening when the throttle is completely closed, and pretty sure it is staying closed. Losts of little stuff still unfinished, and will start tying up all the loose ends next week.

If it really boosts, then you'll see a big difference for sure. I think 2000 RPM for the max boost is too soon. I'd expect at least 4500 RPM for your set up. My turbo with barely no lag reaches its max boost at around 5000 RPM. You'll need to install the boost gauge to see what psi that you have. A boost gauge & a wideband A/F gauge are a must for any custom forced induction set up. Without them, you're like driving in in wilderness.

 

[SuperRunner]

yeah, but with the supercharger it is a ratio, not like a turbo. I guess I am just trying to wrap my head around how RPM's and pressure ratios are determined/obtained and how the bypass valve regulates that. Still cloudy up there.

 

[SuperRunner]

here is a vid I will try to get an action video tomorrow. Right now I have the stock single pipe connecting the two sides. I will probably go X pipe for better upper RPM performance.

http://www.youtube.com/watch?v=XAw0Q0htSyk

 

[SuperRunner]

So in thinking about the bypass valve. Doing some more reading, it is not really REQUIRED so to speak. It will just cause the supercharger to cavitate, robbing HP generating lots of heat. The bypass valve just helps out ONLY when the manifold is under vacuum. I used to think...well it will NEVER be under vacuum if the SC is always pushing air. BUT...With the throttle body close the SC can't draw in any air(cavitation). No air, no boost. Boost will only be regulated by the pully size.

I theory I should see max PSI at WOT and the engines LEAST efficient RPM. As engine efficiency(volumetric efficiency) goes up, boost pressure drops.

Hmm, I like turbo's better, as this concept is backwards.

Better to get a supercharger that is too big, and electronically control boost at a set level with an electronic bypass valve

 

[JustenGT8]

You can see pretty much full boost by free revving, you will def be boosting at any revs at full throttle once you are on the move.,

You are right in that you don't need a bypass valve but it does make the setup far more efficient. For testing purposes though disconnect the vac lines and stiffen the spring right up.,..this will at least eliminate the bypass as the issue.

 

[SuperRunner]

ZERO BOOST!!!!!

I don't see even the slightest bit of positive pressure.

I did a manifold pressure test, which I didn't think could be done on a V8. I figured there would be overlap somewhere.

Anyway, I had a pressure gauge on each side of the supercharger. I could get the manifold to see 20+psi of pressure no problem, and of course the pulley would spin. I could then STOP the rotors from turning, and there was almost NO CHANGE between the two pressure gauges.

So, I can only assume that the supercharger is worn out in order to bleed that much air. Yes/No?

 

[Cobber]

Make sure your idle speed control valve is closeing off when under boost.
Show us some pictures of how you have plumbed that up.

Better still re locate it to the inlet side of the supercharger and blank off where it currently sits on the pressure side.

 

[SuperRunner]

Yup, my ISC valve isn't closing for some reason. I will move it BEFORE the the supercharger. Thanks cobber.

So I only made 3psi, but I do have a large pully and the custom intake with the radius ports. Even at no boost, I felt a definite power increase over the stock manifold.

And....I just broke a motor mount from the extra torque....GREAT!!!

 

[JustenGT8]

Good news then even the broken engine mount is good in a way...shows how much extra torque you have

 

[SuperRunner]

Well, by going to a 2.5" pulley, I am able to get 7psi intercooled. I must say, I am NOT impressed with the M90 at all. I could buy another M90 that is in slighly better shape, but I don't know if that will really help much.

I am also not impressed with the 7psi. My supra with 7psi has way more torque than this. Probably due to my ported/polished heads that flow 230cfm on the supra, and only around 170cfm on the 1UZ.

I have come to the conclusion that for these 1UZ to make any real power, MAJOR head work needs to be done.

More to come.....

 

[stevechumo]

Nice...7 psi...The head work should be done to improve the flow. However, I'm not sure what you mean by not being impressed. My turbo runs 6 psi and it's very torquey at low end. I can spin the rear easily at launch and it goes to 60 mph very quick, and keeps pulling all the way to 100 mph easily. I see a big difference between stock and 6 psi of boost.

 

[JustenGT8]

Well, by going to a 2.5" pulley, I am able to get 7psi intercooled. I must say, I am NOT impressed with the M90 at all. I could buy another M90 that is in slighly better shape, but I don't know if that will really help much.

I am also not impressed with the 7psi. My supra with 7psi has way more torque than this. Probably due to my ported/polished heads that flow 230cfm on the supra, and only around 170cfm on the 1UZ.

I have come to the conclusion that for these 1UZ to make any real power, MAJOR head work needs to be done.

More to come.....

ORLY ???

I got 265rwkw on 6.5psi...totally stock engine....show me a 2J that does that

and on it goes....320rwkw on 12 psi....400+rwkw on 17psi...and now with new intake manifold approx 305rwkw on 11psi (TBC)

 

[SuperRunner]

I guess I am just used to the supra. After that, everything feels slow. I could be putting down 500rwhp, and that would still feel slow to me. Definatly not like breaking tracking at 80+mph. But even running around at 7psi on stock compression, it felt like it had more power than the sc400. Again, probably due to the effeciency of the head.

I need to have my buddy with his stock sc400 come over so I can tell the difference.

I can't really take it out past my neighborhood yet though. I have a state inspector coming on Monday to check out the vehicle so they can re-issue a title. Then I can take it out and really open it up.

 

[JustenGT8]

Weight, auto, ECU....all will hurt how fast it feels com,pared to your Supra...it's not all engine. With an extra litre of capacity the UZ will stick it to a 2J until well over 400rwkw which is where the superior engineering of the 2J starts to shine and UZ needs to be opened up.

 

[SuperRunner]

Well, lets do a little math.

170*8 = 1360
220*6 = 1360

Wow, same amount of inflow.

Now subtract the 50+hp needed to run the supercharger, crappy cams and crappy ECU. I know I could really get the 1UZ to perform VERY WELL, but in is stock form, performance wasn't the main goal. Fuel efficieny was.

So you say you got 265rwkw at 6.5psi? That would be what, 344rwhp? I have yet to see someone push that much HP on a supercharger, especially with stock ECU, stock exhaust.

Sorry, but my supra felt much more powerful at the same boost. Maybe if the sc400 was turbocharged instead, it would feel a bit better, but the loss from driving the belt really sucks. This will definatly be my last roots supercharger setup.

 

[stevechumo]

I'm not sure what year of Supra that you have, and what rwhp that it puts down. The SC400 with 7 psi will add about 96 rwhp that roughly equals to 133 bhp. You might not feel it's powerful comparing to the Supra might be from the SC sluggish tranny and the LSD. After I upgraded the stock torque converter to Lextreme torque converter with 2800 stall rate, it's a huge difference. Then I replaced the worn & cracked drive shaft bushing, it's a little bit more responsive when the power goes to the rear wheels quicker without twisting as much as the cracked one does.