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Jetting RX-1 MCXpress turbo - HURRICANE's turbo springs

TT said:
Rxrider - how many mm did you cut the OEM springs down?

I have a spare set - I guess I will give it a try also. Someone has to be the first one to try with the MPI/bender kit.

Only 15 psi - You are grazy. I'm just getting used to mine, and turning up the boost in baby steps. I guess I have small balls - LOL
Click to expand...

HAHAHA well I'm in my 3rd season turboed, it took me until late February last year until I was confident enough to start turning the boost up. I had a whole day of testing, running it on a mix of pump and race fuel. I started out at 11 lbs on the WG giving it half a turn at the time on the Hallman Pro RX with the stiff spring installed. Turn up the controller, testrun, cooling down riding a mile or two in loose snow, turn up the controller, do a testrun......you know the drill. I finally ended up at 16 lbs. I carefully monitored any oil consumption, coolant loss, you name it. Prior to going up in boost I have loaded my Supertips according to Teds suggestions. At the end of the day I was bang on at 16 lbs. I knew I had enough octane for 18 lbs so I gave it a try. WOW plain sick power. I will have to try that again when I get hold of some racefuel.

Make sure your jetting is OK and you have the compression lowered if you intend to ride it at 16 lbs on pump gas. I run Wiseco 10:1 pistons and 2 stock head gaskets stacked.

You are wise taking your time going up in baby steps, you have to get to know your engine and watch her carefully every step of the way when going up in boost. One more thing, I never do back-to-back-to-back runs it's a recipy for disaster. Things get dangerously hot. I have seen what can happen, luckily it did not happen to me.

Jan-Ove
rxrider
 

I only have a GT2554R turbo - and three stacked head gaskets - so I'm shooting for 12 psi. I will have to upgrade the turbo going over 12 psi.

I had the same "problem" as Turbo tim had with his charged tube made of titaium. It runs leaner than the stainless steel ones. I had to block off the pitot jet to make it run with 135 main jets. That is with no pressure leaks (everything glued, alu. t's and alu. carb caps).

Getting the AFR right with the MPI/Bender kit seems takes more time than with the MCX kit - but I will get there. :exc:

Even with the pitot blocked off it ran a little lean. I'm shooting for good AFR with a 600 jet in the pitot at low boost. So I rejetted main jets (137,5) and turned out the pilot screws half a turn (2,5) last night.

I can't wait for tomorrow. I feel like a kid waiting for Santa Clause - LOL.

I will not turn up the boost before I have AFR perfectly dialed. :jump:
 
On the MCXpress kits the AFRs doesn't change much when going up in boost. Some say it's getting leaner when going up in boost, not true in my sled running a MCX turbo kit. This may be a whole another story with your Bender kit.

I know that feeling LOL :) I'm going out tomorrow as well, for a test ride with the turbo and for a long distance trailride on my Apex RTX .-)
 
The verdict is:
I cut down the springs a little too much, I cut them down 32 millimeters. When cut down 20 millimeters they worked better.

I will buy the turbo springs from Hurricane before next season, I may also jet down the mains from 132.5 to 130.0
 
HURRICANE's turbo springs are installed.
Stock pilot jets at 17.5
Pilot screws at 2 turns out
Needles at #3 position (in the middle)
Main jets at 132.5

Many things have changed since last season. The MCX Mitsu turbo is history.

My setup for 2009 season:
- NFS2 stage 3 turbo header and downpipe (going front mount)
- Powder Lites prepared Garrett GT2860RS-739548-5 turbo, ported and ceramic coated
- Powder Lites oil and coolant kit for the turbo
- MCX Intercooler
- MCX (Malpassi) fuel pressure regulator
- MCX (Bosch) fuel pump
- Bombardier REV gas tank

I will post jetting results from tuning the sled when the snow flies. Can't wait to start tuning with HURRICANE's turbo springs installed :)
 
Jan
Those springs will lean out your mids to where you want it. Don't let that fool you when your jetting. Change your main jets for wide open throttle and the mids will come in for you on there own.
Dave
 
Skydog - Long time .... I'll let you know how she runs asap :)

Dave - Thanks for your advice, I'll leave it like it is and run it. Then I will change the mains if needed.

Last season I had the needles in the #2 position to fight the fat low end, but set that way it sent my high speed 3/4 throttle AFRs scary high at low 14s. Boost level was 12-14 lbs at 3/4 throttle. Would you consider this a dangerous AFR level? Anyway I though it was no good so I did not run it like that very often, 5/8 and WOT had about perfect AFRs. WOT AFRs was at 11.2-11.7 depending on conditions and 11.4-11.6 most of the time runing the 132.5 main jets.
 
Your right ,the needle clip is to tune the low end but also affects the top end.I set the clip for the low end first ,then play with the mains after. I usually jet for between 11.8 to 12.5 under load and you can let it lean out in the low end and mids. Say about 12.5 to 14 at idle,12.5 to 13.5 mids and 11.8 to 12.5 under heavy load.
 
Dave - your input is very much appreciated, thanks.

Pilot screws at 2 turns out gave me idle AFRs at 14.5-14.7 and even higher AFRs if left at idle for a minute.

I had a problem last year when giving it wot from a standstill. AFRs where decent until boost came on (5500-6000) then it would plunge down to low 10s (sometimes high 9s followed by misfireing). Lowering the needle one clip position to #2 did cure the misfireing, but it felt soft until rpms revved past 7000 (and 10 lbs boost) then it cleared up with AFRs at 11.2-11.7 depending on conditions.

My hope is that the HURRICANE's turbo springs will lean out the low end bringing up my AFRs from low 10s to somewhere in the low 11s or higher. Result=improved throttle response, problem solved :)
 
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