C30-94 boost levels?

[Ninjabogey]

Hi all

Can I ask what levels of boost people are getting from their rotrex units. I have read all over the web and consensus appears to be around 13psi at 105krpm. Other documentation claims up to 18psi.

My install is outputting 10.5psi running at 105k at 11k rpm after running through a large intercooler and a good few 90' hoses to reach the plenum. I don't have a huge level of confidence in the bov and it could be opening early and could overdrive the charger a bit but boost is a few psi lower than expected even assuming I lose 1.5-2 psi through the pipe run.

Any thoughts or suggestions?

Cheers
Paul

 

[vampire]

With a 85mm on the cranck and 80 on the charger ,so around 6% overdrive we had just near 1 bar, so 13/14 psi on the gauge . measured at 9000 rpm, no intercooler and gauge was connected to the plenum, so before the throttle plates and at 50% TPS. Next time on the dyno at full throttle we'll use EcE.datalog to see the exact boost figures.

 

[Ninjabogey]

Cheers for replying. My boost appears low and I am overdriving slightly less than you but I'm not sure whether or not to buy another bov. I just have 25mn vent to atmosphere forge unit with no adjustability. I may reduce the charger pulley by a few mm and change the bov anyway but then need a remap

Anyone else?

 

[ROTREXPOWER]

Is this a new type TTS kit or your own? Running WOT to Max revs on a 1:1 ratio you should easily see 16 psi if you don't have belt slip. Remember revs = boost not like a turbo, The supercharger boost will just keep climbing to the limiter. 50% throttle will not see anything like full boost if you are measuring engine side of the throttle body (the right place). You should set the blow off valve to lift on idle and part throttle, when you crack the throttle is should slam shut. If you have a small ic you will get a big pressure drop and lose as much as 6-8 psi so be careful. Check your boost before the ic and after on WOT. Hope this helps.

 

[Ninjabogey]

Thanks Richard. I am running the setup in a car and worked with Nick at Playskool on the project as they are much closer to me than you and had some success with his own car.

It's a 2010 dated rotrex with a DIY mount and drive mechanism with your tensioner and plenum. Running just over 1:1 and only seeing 10.5 lbs. I had expected to be seeing more. I have a large intercooler that I was recommended to run but wasn't expecting to loose quite so much boost. Hopefully I am seeing improved intake temps to counteract the boost drop. I am feeding the map sensor off the vacuum. I'm assuming that's an acceptable way to read boost?

The bov is fluttering at idle but does snap shut on full throttle. I have picked up an adjustable turbosmart bov to try and will also recirc rather than vent to atmosohere. The engine mapper thought the bov might be opening early as it had no adjustment.

On the dyno there was no sign of belt slip. Any easy way to check?

Thanks for responding. I know you are the man on this stuff. I am enjoying the project and its still early days

 

[ROTREXPOWER]

Its probably belt slip check out how much wrap we have on our new systems, I picked up 5 psi + over our previous kits with just 180 deg of wrap. How many rib belt are you using, you need at least 7. Pressure drop over ic's is often overlooked we have seen huge differences, short ic's as wide as possible are the way to go, long ic's have huge drops.

 

[Ninjabogey]

Hi

Thanks for the help. I now have a goid idea what i am looking at now and have a plans to check for leaks and will look at options to optimise belt wrap. Will need to get my injectors updated first

Will report back on progress. Thanks again.

Paul

 

[ROTREXPOWER]

We have just built a c30-94 kit into a kit car and had to use a lot of 2 inch pipe to and from the fmic and the pressure drop is huge but the air temp is very low. We still made what we wanted at 300 whp at 11k with 10:1 comp. 10 psi lots of ign retard so its very safe.So often the design is compromised by physical constaints. It on our tts performance facebook, worth a look.

 

[Ninjabogey]

Had a look. Top job. I need to replace my injectors and focus on belt slip but happy with 250 rwhp at present. Recommended route for car guys and very controllable on the limit