power boost valve
Discussion
Look out Dave, long winded answer coming up…
My S1 111S was standard and I was happy with it. I recently knackered the manifold by stripping the thread trying to replace the lambda sensor. Instead of replacing it with standard, opted to fit a shiny 4-2-1 manifold and a free flow cat. The car ran very sweetly afterwards although there was a noticeable lack of oomph. It sailed the MOT with emissions registering fresh air. I couldn’t understand it though. I thought that the exhaust/cat might produce a tiny performance increase but NOT make it worse!
I then looked into this whole “111S needs back-pressure” thing. Do I really have to put a clogged up standard CAT back on to restore my performance?! Eh?!
Apparently not. In simple terms, this is what I’ve found out. The car’s fuelling/mixture is tuned with it’s exhaust system. Monkey with the exhaust (like putting on a free flow cat or decat pipe) and you monkey with the fuelling requirements. For some reason, it seems that the 111S is particularly sensitive to this monkeying. People have been here before and it seems that to fix it, it needs to be ‘richened up.’ Technical eh? The correct route would be to get a programmable ECU and get it remapped. The cruder approach would be to just fit something that (slightly) increases the fuel pressure throughout the rev range. This is the POWER BOOST VALVE that you’re talking about.
So earlier this week I fitted one and took the car for a test drive. Night and day difference.
I’ve got my old car back! In fact, it seems to have much more ‘go’ earlier in the rev range. It is adjustable and as I don’t want to overfuel the thing, I’m off to the rolling road at SRE today to get it adjusted correctly. I have been there before, so I’ll be able to compare before and after performance figures. I’ll post them up for you later. Either way, I’m not expecting any great hike in performance – you need a DVAPOWER operation for that.
In summary – if your car is standard, then leave the POWER BOOST VALVE alone.
If you’ve lost the cat and therefore lost some performance – it’s well worth a go. There’s an argument that says perhaps I just have a lazy old pressure regulator. If that’s the case, the boost valve is also a good replacement.
I’ll report back after the rollers.
My S1 111S was standard and I was happy with it. I recently knackered the manifold by stripping the thread trying to replace the lambda sensor. Instead of replacing it with standard, opted to fit a shiny 4-2-1 manifold and a free flow cat. The car ran very sweetly afterwards although there was a noticeable lack of oomph. It sailed the MOT with emissions registering fresh air. I couldn’t understand it though. I thought that the exhaust/cat might produce a tiny performance increase but NOT make it worse!
I then looked into this whole “111S needs back-pressure” thing. Do I really have to put a clogged up standard CAT back on to restore my performance?! Eh?!
Apparently not. In simple terms, this is what I’ve found out. The car’s fuelling/mixture is tuned with it’s exhaust system. Monkey with the exhaust (like putting on a free flow cat or decat pipe) and you monkey with the fuelling requirements. For some reason, it seems that the 111S is particularly sensitive to this monkeying. People have been here before and it seems that to fix it, it needs to be ‘richened up.’ Technical eh? The correct route would be to get a programmable ECU and get it remapped. The cruder approach would be to just fit something that (slightly) increases the fuel pressure throughout the rev range. This is the POWER BOOST VALVE that you’re talking about.
So earlier this week I fitted one and took the car for a test drive. Night and day difference.
I’ve got my old car back! In fact, it seems to have much more ‘go’ earlier in the rev range. It is adjustable and as I don’t want to overfuel the thing, I’m off to the rolling road at SRE today to get it adjusted correctly. I have been there before, so I’ll be able to compare before and after performance figures. I’ll post them up for you later. Either way, I’m not expecting any great hike in performance – you need a DVAPOWER operation for that.In summary – if your car is standard, then leave the POWER BOOST VALVE alone.
If you’ve lost the cat and therefore lost some performance – it’s well worth a go. There’s an argument that says perhaps I just have a lazy old pressure regulator. If that’s the case, the boost valve is also a good replacement.
I’ll report back after the rollers.
…back from the rollers and the results are in.
Drum roll…. I’m back where I started!
4-2-1 manifold + high flow cat + readjusted fuel pressure = same as standard.
Well, that’s not strictly true, there’s a titchy 3bhp increase at the top end (6900rpm) over last year’s measurement (from 139 to 142bhp) but the torque etc is the same.
We did need to up the fuel pressure to get that back though as we were 9ft/lb and 10bhp down on the first run (mixture too weak.) We also went ¼ turn too far and performance drops off if it’s too rich.
So, in summary. If you’re looking for a performance increase…forget it. Save your money for a proper engine mod. In fact, until that happens, keep your standard manifold and cat too. If I’d gone through all this expense for a performance increase (instead of just passing the MOT) I’d be gutted. If you’ve decat-ed and want to put the performance back, then the POWER BOOST VALVE will do the job, otherwise, leave it all standard.
Hope that helps.
Drum roll…. I’m back where I started!
4-2-1 manifold + high flow cat + readjusted fuel pressure = same as standard.
Well, that’s not strictly true, there’s a titchy 3bhp increase at the top end (6900rpm) over last year’s measurement (from 139 to 142bhp) but the torque etc is the same.
We did need to up the fuel pressure to get that back though as we were 9ft/lb and 10bhp down on the first run (mixture too weak.) We also went ¼ turn too far and performance drops off if it’s too rich.
So, in summary. If you’re looking for a performance increase…forget it. Save your money for a proper engine mod. In fact, until that happens, keep your standard manifold and cat too. If I’d gone through all this expense for a performance increase (instead of just passing the MOT) I’d be gutted. If you’ve decat-ed and want to put the performance back, then the POWER BOOST VALVE will do the job, otherwise, leave it all standard.
Hope that helps.
thanks for the long winded answer i do have a sports manifold cat and exhaust my car was not standed when i got it so i cant comare i was lead to belive that the ecu would sort out any fuleing probs .
my other option was to get an the car chiped but it does work out more expensive iwould be cuft if you would let me know what they say when you get the car ran up and also what vavle you got and where from thanks alot
my other option was to get an the car chiped but it does work out more expensive iwould be cuft if you would let me know what they say when you get the car ran up and also what vavle you got and where from thanks alot
It's the one from Eliseparts. (If you end up getting it, let me know as I have a few tips for fitting it without bad language.)
As your exhaust system isn't standard, and as you dont know how a standard 111S 'should' perform, then it might be worth £90 to see if you can get some extra performance from what you have now. As far as I can see, there's nothing else to be lost as you can always set it at the same pressure your standard car runs anyway.
As your exhaust system isn't standard, and as you dont know how a standard 111S 'should' perform, then it might be worth £90 to see if you can get some extra performance from what you have now. As far as I can see, there's nothing else to be lost as you can always set it at the same pressure your standard car runs anyway.
dave111s said:
thanks for the long winded answer i do have a sports manifold cat and exhaust my car was not standed when i got it so i cant comare i was lead to belive that the ecu would sort out any fuleing probs .
my other option was to get an the car chiped but it does work out more expensive iwould be cuft if you would let me know what they say when you get the car ran up and also what vavle you got and where from thanks alot
Could somebody please translate?my other option was to get an the car chiped but it does work out more expensive iwould be cuft if you would let me know what they say when you get the car ran up and also what vavle you got and where from thanks alot
Dave, without being patronising (you make no mention of previous cars on profile.....you could have had Ferraris for all I know....), concentrate on learning how to drive the car instead of chucking money at the engine. Driver training, brakes, then suspension, would be best upgrades in that order. The car has plenty of power as standard.
Make a long term plan. If the car is a 'keeper' then spend away. Otherwise, think very carefully about exactly what you want to achieve in relation to cost. Don't spunk money on gaining 2bhp here and there only to sell it in year, and don't become obsessed with pub talk bhp figures, because they mean little in the real world...
Make a long term plan. If the car is a 'keeper' then spend away. Otherwise, think very carefully about exactly what you want to achieve in relation to cost. Don't spunk money on gaining 2bhp here and there only to sell it in year, and don't become obsessed with pub talk bhp figures, because they mean little in the real world...
TIPPER said:
dave111s said:
thanks for the long winded answer i do have a sports manifold cat and exhaust my car was not standed when i got it so i cant comare i was lead to belive that the ecu would sort out any fuleing probs .
my other option was to get an the car chiped but it does work out more expensive iwould be cuft if you would let me know what they say when you get the car ran up and also what vavle you got and where from thanks alot
Could somebody please translate?my other option was to get an the car chiped but it does work out more expensive iwould be cuft if you would let me know what they say when you get the car ran up and also what vavle you got and where from thanks alot
If you have a problem with this then I was out of order. Please accept my apologies.
Just thought that I'd add the Hollywood is talking a lot of common sense. Its unlikely that your butt dyno will notice any increases of less than 10% in power and to acheive that you need a bit more than bolt on mods.
All Elises are pretty damn quick up to about 80 and on the road there's not a lot between any of them. On track the driver will make far more difference than a few extra bhp.
I'd spend money on brakes and then suspension and then look for more power.
thanks tipper i really carnt spell for toffy i have that nasty thing that begins with a d
donesnt stop me driving
i have had my elise for 3 year now and did three trake days last year i have had some driver traning but mor is always good
i did start with the brakes first i have s2 suspension and a full sports exaust most of the mods where done when some thing went wrong with the standed ones and i agree they is nothing rong with the power
i may get the car on a dyno and see if they is a problem befor i start doing any thing
and sorry once again for the spelling
donesnt stop me driving
i have had my elise for 3 year now and did three trake days last year i have had some driver traning but mor is always good
i did start with the brakes first i have s2 suspension and a full sports exaust most of the mods where done when some thing went wrong with the standed ones and i agree they is nothing rong with the power
i may get the car on a dyno and see if they is a problem befor i start doing any thing
and sorry once again for the spelling
I'd be looking to save the pennies and maybe get Dave Andrews K06a kit. Alternatively talk to Rog at Sabre Heads.
As you may be aware both are highly respected in the world of K series engine tuning. What they don't know probably ain't worth knowing.
Just a thought though. Not sure if the S1 111s has the C/R box. Very worthwhile upgrade if not (made a huge difference to my 120bhp S1).
As you may be aware both are highly respected in the world of K series engine tuning. What they don't know probably ain't worth knowing.
Just a thought though. Not sure if the S1 111s has the C/R box. Very worthwhile upgrade if not (made a huge difference to my 120bhp S1).
TIPPER said:
I'd be looking to save the pennies and maybe get Dave Andrews K06a kit. Alternatively talk to Rog at Sabre Heads.
As you may be aware both are highly respected in the world of K series engine tuning. What they don't know probably ain't worth knowing.
Just a thought though. Not sure if the S1 111s has the C/R box. Very worthwhile upgrade if not (made a huge difference to my 120bhp S1).
S1 111s has C/R box as standard.As you may be aware both are highly respected in the world of K series engine tuning. What they don't know probably ain't worth knowing.
Just a thought though. Not sure if the S1 111s has the C/R box. Very worthwhile upgrade if not (made a huge difference to my 120bhp S1).
Edited by Gad-Westy on Monday 3rd December 11:21
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