I thought I would run this past a few people who may know a thing or two on the subject!, hope you don't mind. A friend of mine said that he has recently seen these for sale for mx5's, the claimed benefits being quicker throttle response, faster acceleration etc.

They mention 'rising the fuel rate' to 1.7:1? All I am really concerned with is are they worth it? I wouldn't expect a lot of difference but it may eliminate the 'nodding dog' effect which I sometimes have on my 93 1.6 roadster when pulling away, they would however possibly result in an increase in fuel consumption during harder driving? Has anyone out there had any experience of these 'little things' at all? (5/00)
Someone on the list attached one of these (bought from Moss) to his '90 Roadster. According to his timings he shaved about 0.5 seconds off his 30-70 timings (not entirely scientific) but IIRC he swore there were definite improvements in performance. The only thing he had to fiddle with was some adjustent screws. His current set up makes the car pop and bang slightly on the overrun but I think he likes it that way. Rolling road tuning would sort it out. His Roadster has some head work,4-2-1 manifold , sports exhaust and Jackson CAI. No-one else seems to have taken up the mantle of these valves AFAIK. They seem like pretty good bang for the buck. (5/00)
Do they just boost fuel pressure? I'm not sure how this is supposed to help. A bit like people who fit high-flow fuel pumps when their fuel delivery is just fine anyway. (5/00)
The standard car has a fuel pressure regulator working relative to inlet manifold pressure/depression (by bulkhead at the end of the fuel injector fuel rail) ... this valve alters the pressure rise rate relative I guess to vacuum (i.e. putting your foot down to accelerate) .. more fuel pressure over the same injector hole/time open for injector gives more fuel ... which may give you more acceleration .. or may over fuel the engine and slow you down ... trials are needed to set them up. (5/00)
But in closed loop mode the ECU uses the O2 sensor. In open loop mode (WOT) there would never be a vacuum so this pressure regulator won't be using any kind of slope. Can't you get the same effect by just getting your fuel pressure right? I guess a dyno. is required for both tasks. Is the stock FPR adjustable? (5/00)
Kinda - the only adjustment is to crush the casing slightly - this will up fuel pressure. (5/00)
Just chatting to b/f about the boost claims, and he suggested also mentioning the following, assuming everyone already uses super unleaded too.. (sorry if this is old news, blah blah)...think he got it from another list. "To raise the octane level of the fuel they are using "Millers Octane Booster" is the one to go for. It raises octane by just over 2 points. If you have a N/A care then it should allow you to increase the timing a little bit. For those that have turbo/super charges it will reduce the risk of pre-detonation and allow you to increase boost pressure a little. Bear in mind that for imports, jap fuel is 100 RON and the engines are designed to run efficiently on that. When they come over here to the UK and run on our crap fuel...performance suffers." (1/01)

Just used this 10K boost stuff - here's how I got on.

The car in question was a SE MkII, 1600, 1993, 48k on the clock.

1. As per the instructions, I warmed the car up (and in my case) took off the K&N filter. With the help of my girl holding the car at 2500 revs and a screwdriver to hold the airflow meter open, I squirted half of the 1st can into the intake.

2. Let it stand for 5 mins

3. Then used the remaining contents of the can.

4. Then I went for a 10 minute drive...

5. Well, It spluttered a bit but didn1t feel much of a difference... Time for the second can... Same as the first can, however I let the can stand for 10 minutes before having another drive.. when I pulled away this time as I started to accelerate, the car lost power, and the engine cut out! I re-started the engine it coughed and spluttered and plumes of white smoke came out of the exhaust but off I went again. As I accelerated again the car spluttered a little more, there was more smoke but then it was fine. I carried on driving for a another 10 minutes and the car behaved normally..

My impressions? Well I can honestly say the car feels livelier! - Really! I know you tend to get that feeling after you play with the engine - but I speak as I find! I don1t know if the fuel economy will improve or the emissions will go down or whether Arsenal will win the premiership. But right now I have no regrets on spending 25 quid on this stuff. (1/01)