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Fuel Pressure Regulator?

1105 Views 11 Replies 7 Participants Last post by  Simon Linton
my only performance mod is a MBC, running in my 850 turbo...set at about 14 psi, i get 14.2's @ the track...now, if I go to 15 psi, i get 14.3's, which suggests to me that either the exhaust is the restriction, or the fuel pressure regulator..now, i don't have an A/F meter, but do you think getting a fule pressure regulator (better one from somewhere?) will help, even just to be able to run 14 psi safely (i run about 11 daily because i'm not too sure about the lean factor,)...but would a better fuel pressure regulator help?
how about the ones from the new S70 T5's, or C70's...since they have a higher boosting turbo, do they have a FPR that could suite
Thanx guys..

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Oh boy, do you have a lot to learn. As much as I would like to see the whole MBC crowd rot and blow their engines. I will just share some notes with you since I'm such a nice guy.
Again like my previous email to you, it's not going to be the nicest thing anyone going to say to you.

It seems as if you have managed to get your car to run down that ¼ mile at a very respectable short time. However, I can almost assure you that your engine won't be so happy in the long run. I know how you want to save money and all by doing just the MBC, but you are not really saving that much. You can't really cheap out on power. Here is why…

You really think the FPR will do the job? No, it will not. Even with FPR installed, you will need the car to be properly tuned…it's not a 1-2-3 MBC shade tree mechanic job. Why bother when your ECU is not even tuned to accept all these add on aids? Why bother when your bottleneck is not just the turbo, rods, lean condition, but also your exhaust system? If you are lucky to get away with other bottlenecks, to have your engine dyno tuned right; you will still need some sort of external fuel management system to piggyback with YOUR STOCK ECU.

No, you don't want the factory FPR from the 70 series or the R series, it's pointless. They are still not built for you to do all the adjustment. Rising rate might do, but I don't know for sure. If you are lucky enough, you will have a fuel return line in your car that will allow you do install FPR fairly painless, but that's assuming you do have a fuel return line. If not, you will have to somehow tap into your fuel rail and go from there. I have an Aeromotive one in case you haven't read it from this forum.

However, before even thinking about the FPR, have you wonder if your fuel pump is efficient enough, how about the injectors? There are so many other variables to look into and you have not even started out w/ your normal exhaust & ECU upgrade routine. Sure you got a good 14.2 time slip, and most likely b/c you are running very lean (more power, but risky; rich => less power, safer for the internal).

I can seriously tell you that your stock FPR is not your main concern now. Get the other things done first, then you can get a better feel. Learn how to walk first before you want to start running. Again, this as helpful as I want to be today, I think Phill is going to wonder why I'd be helping the MBC guys, especially you.

Then of course, you don't need to listen to me. You can just keep on doing what you have in mind, I'm curious to find out what will become of your car.

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Wow, harsh. I've never heard anything about this mbc mod. Sounds like it could be short lived from Kai's comments
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Originally posted by Spearzy:
Wow, harsh. I've never heard anything about this mbc mod. Sounds like it could be short lived from Kai's comments

It's not bad, but those who just simply add this unit without any further fine tuning is just not a smart move.
I must agree that my reliablity will not be as good as stock..but i'm not sure why I should be all that worried..and here is my own defense.. I have my MBC set to about 11-12 psi, and when i go to the tracks, i run it @ 14psi... when my car was stock, i would get spikes @ around 12 psi...which leads me to conclude that the ECU, fuel pump, and reglulator, injectors,and such are equiped to handle around 12psi..now given different altitudes, I know that all car manufacturers give themselves a "safety margin"..therfore, other volvos at different altitudes, and temperatures will experience different boost spikes as well..by raising my daily psi boost to 12, i don't really see the enormous danger in exceeding the ecu's fuel/ignition curve and such..and given that i can achieve 12 psi STOCK, that should be well within the safetly margin which volvo has intailed..granted, i do not know the limit, but by me occasionally running it at 14psi @ the track, i do not see the harmm..

but i must agree with you about the failure of just adding an MBC....IF i went, say autocrossing...my daily driving routine is very easy going on the car...usually kept under 6 psi... therefore minimizing the stress on the pistons, connecting rods, transmission...etc...

i hope that no one was scared away from that other post..i have talked to a guy w/ 90,000 miles on his 850, and had a MBC in for 30,000 of it...trouble free..
the key is not to go wild w/ boost..and careful driving..

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*yawn* evryone wants power for nothing. but still, if your happy with your doing then hey go for it! its just that you could get more if you build a base. previous posts show in detail what will get your car purring for the least amount of money, so have plonder around, then ask questions..

Kai is right! I've been working and learning with him for a couple of years now. He's been there and done that. So have I! I've done some extreem stuff with my 850 as well. Had the car on the dyno with 264 WHP with a dead FPR. Repaired the FPR and the car was much faster and happier. Anyhow, don't expect too much from the car untill you begin to build it from the bottom up. If you push it too hard...you'll end up pusing the car home. I've done that as well. Just go about things in a logical path...don't jump into it blindly.

Hey Matt, how you doing? I would love to hear of the Logical path. Kai still hitting hard I see, check the number of posts he has, did you not have a name for people like that?
Hey Sean!
Long time no see. I've been meaning to give you a call but have been busy working my new job. 10+ hour days and late nights, not a good mix. Haven't even been able to replace my rear calipers which have been bad since the accident.

Regarding the logical mix, it all stems from my experience on the NASCAR team and 10 years of engineering. It really is the little things that all add up. Also, I'm a diehard fan of great ECUs.

Well...about Kai...He's just being Kai. Power hungry and lovin it! Can't blame him though. After the last few rides in his C70, I feel like my 850 is a toy. So...what was that word we had???

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Originally posted by 1FASTBOX:
check the number of posts he has, did you not have a name for people like that?
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Guilty as charged!
I have to agree wholeheartedly with Kai - our club also has members who want power for little effort and outlay; they are chasing an illustion pushed by uncaring after-market companies who make inflated claims of boosted HP and give no
guarantees regarding long-term reliablity.

The best way to get a more powerful car is a) buy one or b) go to a company that specialises in the vehicle you own and who gets a lot of repeat and recommended business.

I often refer to Kai's vehicle as the way it should be done; the coordinator of our Performance Section, Phil Wright, is also going down the holistic tuning path and the results speak for themselves on the road and recently on the track.

You can see the car in action on the Performance Forum at http://www.volvoclub.org.uk/w01-0090/cgi-bin/dcforum/dcboard.cgi - sadly my 850R saloon did not do as well since a) I'm a crap driver and b) the weight distribution on the saloons does not like the Castle Coombe circuit as the yellow saloon's progress demonstrates.

Phil's car is modded to the gunwales, but from Kalmar Union who know what they're supplying.

The yellow T5-R is stock.
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