SK400 Posted April 3, 2017 Author Share Posted April 3, 2017 Alright! I finally received the ECU back from the UK, completed a few checks, and finally took her for a spin today. OMG.. felt strong, perhaps more torque than previously but probably the biggest difference is the sound! unreal.. roller barrels with cat bypass changed the RPM tune completely. Pretty decent and "civil" at 3000 RPM but past 5000 RPM, it is a screamer. Plus lots of backfire when I let go of the pedal rapidly. My only concern right now is if i'll be allowed at LimeRock ( able to meet the decibels rules?). I have the r500 carbon fiber airbox which helps... but i guess we will see. Next will be to dyno the car to see what this upgrade really did. Will keep you posted. Link to comment Share on other sites More sharing options...
Kitcat Posted April 3, 2017 Share Posted April 3, 2017 I think intake/exhaust sound is at least as important as hp! My old X-flow had a much better sound than the current Zetec does and was much more satisfying to run up and down the gears. It was also had your engine's off-throttle back fire. It sounded ferocious (but its bark was worse then its bite). I will also be interested in the dyno results. Do you have pre-mod #'s? Link to comment Share on other sites More sharing options...
SK400 Posted April 9, 2017 Author Share Posted April 9, 2017 What a great day on the east coast. Could not resist to take the car out for a spin. Overall, i like the new engine setup, but it feels like it lost a bit of low end torque (under 3000 rpm) or not as responsive off the line .. but then it corrects the the car feels solid and stringer especially above 4500 rpm. I still plan to dyno the car soon, but has anyone experienced a change in torque (lower?) under 3000 rpm when changing to roller barrels, especially when opening the rollers suddenly? just curious.. thanks! Link to comment Share on other sites More sharing options...
simon450 Posted April 16, 2017 Share Posted April 16, 2017 What a great day on the east coast. Could not resist to take the car out for a spin. Overall, i like the new engine setup, but it feels like it lost a bit of low end torque (under 3000 rpm) or not as responsive off the line .. but then it corrects the the car feels solid and stringer especially above 4500 rpm. I still plan to dyno the car soon, but has anyone experienced a change in torque (lower?) under 3000 rpm when changing to roller barrels, especially when opening the rollers suddenly? just curious.. thanks! Hi Seb, for some reason I'm only just catching up on this thread. Conversion looks great, nice job. Funny when Caterham flashed my ecu from R300 to R400 spec, when I built the car, they made the same mistake on the 4:1 rpm read out. Obviously slow learners. Can't wait to see you on track this year and relieved I now have an excuse Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
SK400 Posted April 18, 2017 Author Share Posted April 18, 2017 Simon, good to hear from you. Let's see if this upgrade really helps with lap times.. I suspect that it will still be really difficult to follow you and keep up with your pace!! On a separate note, I have a dyno test and tune appointment on May 6. I unfortunately don't have the pre-readings but still curious to see what the engine puts out with the roller barrels. I'll test with and without the R500 carbon airbox. Link to comment Share on other sites More sharing options...
wemtd Posted April 18, 2017 Share Posted April 18, 2017 seb - who are you using for tuning? Link to comment Share on other sites More sharing options...
SK400 Posted April 18, 2017 Author Share Posted April 18, 2017 P1 Motorsports in Stamford, CT. A good shop. Candidly, I wont be tuning much on the dyno simply because my ECU is locked by Caterham. But they also have great alignment equipment, scales etc and last time I went in for suspension and alignment tuning, the owner did all the work himself on my car. Link to comment Share on other sites More sharing options...
SK400 Posted April 18, 2017 Author Share Posted April 18, 2017 Slight correction - P1 Motorcars Link to comment Share on other sites More sharing options...
Kitcat Posted April 18, 2017 Share Posted April 18, 2017 Can't Caterham tune long distance on the dyno? I thought that's what Tom (YellowSS) did? Link to comment Share on other sites More sharing options...
yellowss7 Posted April 18, 2017 Share Posted April 18, 2017 Mike, you are almost correct. It wasn't Caterham who did the remote tuning, it was SBD an engine turner in the UK. My ECU is the MBE unit like Seb's but mine is not locked so it can be accessed and the map can be modified without having to send it back to Caterham. Tom Link to comment Share on other sites More sharing options...
SK400 Posted May 7, 2017 Author Share Posted May 7, 2017 Well here is the moment of truth folks! I took the car to a Dyno at P1 Motocars in Stamford, CT, for a few pulls. This is a top of the line shop and highly recommended if you want to have some work done on the car and in the region. (engine, alignment, general maintenance, mods etc). Here it is: a) Without R500 airbox cover: 198.42 HP @ 7250 RPM and 158.4 ft-lb @ 6100 RPM at the wheels on the graph, although in the shop, we had read a very consistent 199.5 HP on two separate runs (probably with a different correction value). Shall we call it 200 HP at the wheels? Applying a 10% transmission loss factor (a reasonable estimate for this simple drivetrain, but you tell me) to the 198.42 HP, this translates exactly to 220 HP at the flywheel, which is what Caterham had advertised with the throttle body upgrade kit. I unfortunately do not have a Dyno reading for the original R400 setup but literature puts it at 210 hp @ 7600 rpm and roughly 149 ft-lb at 6300 rpm. I think the 210 HP was right but doubt the 7600 RPM as I know the car struggled past 7500 RPM and hit the cutoff around 7600 / 7700 RPM or so in the past. So net net, a good 9 to 10 ft-lb increase probably really above 4500 RPM, a 10 HP top end increase as a result and a lot more sound, (a lot). Note that this test was conducted using regular 93 octane gas and had noticed significant difference in the past when I used 93 octane from race tracks pump. Also important, I have ZZR tires and pressure was set to 18 psi.. as a few psi more could have changed the readings slightly. Temperature was a comfortable 68 deg and 50% or so humidity. b) With the R500 airbox cover: 192.4 HP at the wheels and 154.4 ft-lb so about a 6 HP and 4 ft-lb of torque drop from the filter only version. Applying a 10% transmission loss correction factor to the 192.4 translates to 214 HP at the flywheel. So this cover saps a lot of power unfortunately and only helps a bit on sound. But it looks good J . The graph below represents with and without the R500 airbox cover. The blue line is without and the red line with. In conclusion, I think the upgrade was worth it but will really pay off on tracks where I’ll be able to run without the R500 airbox cover (example NJMP), where decibels are not an issue. I live close to limerock and normally enjoy a clandestine track day or two there during the year .. but I fear that now, even with the cover in place, I might get myself into decibel trouble for very little horsepower increase (4 HP), not enough to make a difference on lap times. But I’ll see. I’m eying a session on May 22nd and will give it a try. Since the car is now already loud, I may just decide to go full out, and complete the engine upgrade , shooting for a 270 HP setup with the help of the UK tuner SBD. See you soon on a track! Seb http://www.usa7s.net/vb/attachment.php?attachmentid=12601&stc=1http://www.usa7s.net/vb/attachment.php?attachmentid=12602&stc=1http://www.usa7s.net/vb/attachment.php?attachmentid=12603&stc=1 Link to comment Share on other sites More sharing options...
yellowss7 Posted May 7, 2017 Share Posted May 7, 2017 Nice job Seb, Looks like you've thrown down the gauntlet for Simon. We'll see what upgrades he's going to need to keep up with you. Tom Link to comment Share on other sites More sharing options...
Kitcat Posted May 7, 2017 Share Posted May 7, 2017 My "210 hp" Duratec made 165hp at the wheels. Compared to the advertised hp on my cars, including my Miata, Zetec and X-flow, their hp was 20-25% less on the the chassis dyno. Using that formula, u r making 240-250hp at the flywheel. Link to comment Share on other sites More sharing options...
simon450 Posted May 8, 2017 Share Posted May 8, 2017 Nice job Seb, Looks like you've thrown down the gauntlet for Simon. We'll see what upgrades he's going to need to keep up with you. Tom I've had my car tested on on a treadmill and sadly saw less than 175 hp at the camshaft. If I can get within 5 secs of Seb's laptimes at this years Croc & Tom Caterham fest, I will have to be pleased. Link to comment Share on other sites More sharing options...
yellowss7 Posted May 9, 2017 Share Posted May 9, 2017 What? Simon, aren't you going to tell him about the new supercharger? :leaving: Link to comment Share on other sites More sharing options...
Croc Posted May 9, 2017 Share Posted May 9, 2017 My money is on Todd if he can make the event... Link to comment Share on other sites More sharing options...
SK400 Posted May 9, 2017 Author Share Posted May 9, 2017 Not so fast Mike (clearly, you know how to press on my buttons). Just got myself a fresh set of ZZR tires with a24 compound this time. (I just leaned that I've been driving on the harder a64 compound for the last 2 years). So bring it on! All good fun Link to comment Share on other sites More sharing options...
Croc Posted May 9, 2017 Share Posted May 9, 2017 Are you sure you are the only one doing engine mods? :leaving: Be careful with the a24 compound - I chewed through 2 left tires to the belts in 1 day at Lightning. Link to comment Share on other sites More sharing options...
yellowss7 Posted May 9, 2017 Share Posted May 9, 2017 Give me B give me a D give me a ... :jester: Link to comment Share on other sites More sharing options...
SK400 Posted May 10, 2017 Author Share Posted May 10, 2017 Really??!? Were you intentionally trying to wear the tires out? I know the bowl is unforgiving for front tires ... but geesu. I hope at least, for the time it lasted, you enjoyed a bit better traction and handling with the A24. If not, well i'll be in big doodoo with tire budget for the year. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now