Ask the Radical Factory #7 – I bought a SR3RSX 2016, I started it and during warm up it was at 80C on the temp. I gave it a couple small revs prolly up to 4 K , the dash display completely turn red at about between 2500 & 4000 was operating properly at idle or up to 2000 Rpm. I just shut it down to find out what is the issue. Can you advise. Thank you, Ken F

Hi Ken, congratulations on your purchase! On an MXL2 dash the alarms are user configurable, and from the factory they are programmed to turn the display red when certain parameters are not met. From factory the alarm will have activated when the engine oil temperature was not above 45 degrees Celsius yet, causing the display […]

Ask the Radical Factory #6 – There’s a lot of conjecture around use of noise killing cans like Supertrapps, decibel devils, and so on. Some people say they are not good for prolonged use due to the back pressure, others say it’s fine but will cut power dramatically. Are they ok to use, and if so, for how long? Are there any you’ve tested out in the field which work, and could you recommend any? Thanks, Raj (@rojid)

Hi Raj Correct, there is a lot of conjecture around this subject and exhaust tuning in general. A common belief which is key to this subject is that some back pressure is a good thing and is required to make good low to mid-range torque, this is a fallacy. Think of the engine as an […]

Ask the Radical Factory Question #4 – Hello, I Have a new to me a 2009 sr3 (chassis #438). Two questions I have are where about in the setting range for the dampers is a good place to start for a high speed fairly smooth track (CTMP (Mosport) in Canada)? The dampers are the intrax racing with the single adjustment knob at the top car has medium Nik link bars front and rear. Second what set up difference change between the Michelin and Hankook radical tires? The car came with a set of each, and I am free to run either in the club racing that I am doing. cheers, Corey Bradburn

Hi Corey, as you know the optimal suspension setup is dependent on driver style, weather, and track conditions.  The latest Radical SR3 Owner’s Manual (SR3 XXR) describes good Initial suspension set up for dry and wet conditions.  These set-ups work well as a starting point for most drivers at most tracks, and the Radical Handling […]

Ask the Factory Q#1 – I am writing to you from Japan. I work in automotive maintenance. I am working on a Radical SR4 engine that will not start. The fuel pump and ignition coil are not working either. I want to check if the engine control module is working properly. Can I have a wiring diagram for the Radical SR4 (Chassis No: SR4 00082j) Best regards, Atsushi K.

A:  Hi Atsushi, attached is a copy of the Wiring diagram that will help you with your car.  The SR4 you are working on shares the same engine wiring harness as the SR3, so the attached SR3 wiring diagram should be very helpful in troubleshooting your issue. Additionally, plugging into the Life ECU and using […]

Ask Phil #14 – Hello Phil, I have a question regarding HD axles for an SR3 RS or RSX. Unfortunately, as you know, we cannot purchase any specifics parts for these axles from Radical, only complete units. Several of us have sourced the tripods to GKN, but we cannot find the specific inner CV hub that was used… Can you guide us in the right direction? Thanks in advance for your assistance. David I. (@hawkster)

Hi David,  Hope you are well. The inner tripod housing with the splined input shaft was originally from Ford Sierra European model at least) and diff size was 7”  The early model Sierra was 6.5”, most popular and bigger spline section was 7”, and much larger “Scorpio” model was 7.5” (much larger).   Hope this […]

Ask Phil #13 – Phil I have a 2019 RXC 600R with 3.5L eco boost and have been using non leaded non ethanol 97 octane renegade racing fuel that was approved by the factory. My supplier only orders this fuel twice a year and I am about to exhaust my present supply. Is it reasonable to use a premium fuel 92 octane unleaded with Boostane Pro to bring octane to at least 97 octane? Boostane Pro does have some ethanol in it from my research and to this point I have not used ethanol or leaded fuels. Thanks for your advice. Gary H. (@ghaas)

Hi Gary  This is quite a late model question for me , however, as we are still doing later systems in our new world there is some basic guidance.  The real answer to this one is to see the engine data.  It has a good chance to cope with those changes, with knock sensors protecting […]

Ask Phil #12 – Hi Phil, my car is an early Radical SR8 (2005) which runs the “closed” MBE ECU that can’t be programmed. Is it possible to buy a similar “Open” MBE ECU. I want to do a few performance upgrades to the cylinder heads and was worried about the effects since the ECU can’t be programmed Could you also recommend the best options for an upgrades and power gains? Regards Josh Broome (@jwb)

Hi Josh,  That’s quite an early SR8, first question is current spec?  Presumably 2.6 motor, and does it have “plenum” intake or 8 separate throttle bodies?  If it’s still on early plenum – there is your most cost effective and biggest hike in free revving and response, for 8 throttle bodies.  If it’s 2.6 on […]