Individual Throttle Bodied TVR 5.0L with Megasquirt
Discussion
Cheers Jooles.
The plumbing down the middle is a tapping from each throttle to give me a MAP reading for the ECU, I want to try to run this in speed density mode rather than Alpha_n if I can as I prefer that, it will also feed the fuel pressure regulator when I get it all plumbed in,
Phil
The plumbing down the middle is a tapping from each throttle to give me a MAP reading for the ECU, I want to try to run this in speed density mode rather than Alpha_n if I can as I prefer that, it will also feed the fuel pressure regulator when I get it all plumbed in,
Phil
Hi,
the throttles are from a 2002 Suzuki GSXR600, they are 38mm internal diameter. The injectors Ive replaced with 310cc/min, but the originals would have done ok as they were 250 I think, but as I already had a set of 310's I used them. The manifolds I made from a sheet of ally and some ally tube a mate gave me, the tube was simply squashed in the vice to give it a oblong end to match the intake holes of the head, the whole lot was then welded up and dremmeled out and polished so it looks and fitted ok. I cheated by using 45deg Samco hose bends to get them upright, it seemed the easiest thing to do and looks pretty good. The remote thermostat came from Reel Steel, £55,
Phil
the throttles are from a 2002 Suzuki GSXR600, they are 38mm internal diameter. The injectors Ive replaced with 310cc/min, but the originals would have done ok as they were 250 I think, but as I already had a set of 310's I used them. The manifolds I made from a sheet of ally and some ally tube a mate gave me, the tube was simply squashed in the vice to give it a oblong end to match the intake holes of the head, the whole lot was then welded up and dremmeled out and polished so it looks and fitted ok. I cheated by using 45deg Samco hose bends to get them upright, it seemed the easiest thing to do and looks pretty good. The remote thermostat came from Reel Steel, £55,
Phil
I did ring Samco up and ask them about them collapsing and they assured me they would be OK, but they arnt actually very long, the middle ones are cut in 2 and have an ally tube in them to get them to turn into the throttles for spacing reasons so they cant collapse at all and the outer 2 I can squeeze them but they dont shut as they arnt long enough if you see what i mean, but I guess I will soon find out
Phil
Phil
The servo is connected to cylinder 4, the middle cylinders are connected as the pipes were welded together first, as to weld in the middle was impossible, so theres a hair line gap between them so they will interconnect. I dont see why it wont work like that, it should be as good as before.
If you need an ECU to control this sort of setup give me a shout as I sell MS's, I will be putting a description on my new site when I get the chance, www.extraefi.co.uk
Phil
If you need an ECU to control this sort of setup give me a shout as I sell MS's, I will be putting a description on my new site when I get the chance, www.extraefi.co.uk
Phil
hmmm, well I chose the throttle size carefully so as they would still give me some control at low speeds and in traffic, a very clever freind of mine says they should be capable of flowing enough air for around 360BHP, so loads more than Im ever going to get out of this, but not too big so as to loss control. I guess now its simply a case of wait and see, I cant change it too much now
Phil
Phil
Matt,
I must confess I feel sequential is one of those things people use to boast about down the pub rather than being of any use or have any real time gains. In a 4 cylinder engine the valve is open for around 30% of the time, so to inject the required fuel within that time period would be quite a feat, especially when you concider at 6000rpm you have 10mSec between one complete cycle, so 30% of that would be pretty damn small! If you could acheive it with huge injectors then your idle pulse width would be so small it wouldnt be possible to control. Im not saying I wouldnt go for it when we get it in MS, but Im far from being convinced its worth spending any money on it,
Phil
I must confess I feel sequential is one of those things people use to boast about down the pub rather than being of any use or have any real time gains. In a 4 cylinder engine the valve is open for around 30% of the time, so to inject the required fuel within that time period would be quite a feat, especially when you concider at 6000rpm you have 10mSec between one complete cycle, so 30% of that would be pretty damn small! If you could acheive it with huge injectors then your idle pulse width would be so small it wouldnt be possible to control. Im not saying I wouldnt go for it when we get it in MS, but Im far from being convinced its worth spending any money on it,
Phil
Hi all,
well I have now had it running and it sounds superb!! Anyhow, the pipes did collapse a little as GreenV8 said they might, but this was easilly fixed by putting the same ally tube I had made the manifolds from inside them to strengthen them. I had decided to connect the throttles with 2 seperate throttle cables attached to the throttle pedals, Im hoping this will be finished by the weekend.
The servo has to come from the engine side of the throttle plates to get some vacuum, as theres no vacuum in an airfilter, only air flow, I dont think that would create enough.
I am going to run mine in MAP mode, I have used this mode since installing the MS (MS has a built in map sensor) but I may have to switch over to TPS (alpha_n) when I put my foot down to keep the fuel efficiency as good as I can, I prefer map as its more accurate to load than TPS,
Phil
>> Edited by daxtojeiro on Tuesday 18th April 22:42
well I have now had it running and it sounds superb!! Anyhow, the pipes did collapse a little as GreenV8 said they might, but this was easilly fixed by putting the same ally tube I had made the manifolds from inside them to strengthen them. I had decided to connect the throttles with 2 seperate throttle cables attached to the throttle pedals, Im hoping this will be finished by the weekend.
The servo has to come from the engine side of the throttle plates to get some vacuum, as theres no vacuum in an airfilter, only air flow, I dont think that would create enough.
I am going to run mine in MAP mode, I have used this mode since installing the MS (MS has a built in map sensor) but I may have to switch over to TPS (alpha_n) when I put my foot down to keep the fuel efficiency as good as I can, I prefer map as its more accurate to load than TPS,
Phil
>> Edited by daxtojeiro on Tuesday 18th April 22:42
I hate to have to say this but Ive given up. I simply cant get it to run right, it coughs and pops whilst cruising, it splutters out of the intakes, it idles really rough and Ive balanced it all, etc, but it simply seems as if its idling on 6 cylinders, may be less. The only thing I can think of is the fuel is sitting on the small ledges where the rubber pipes join the alloy pipes. I could be wrong of course. I also have a very very small join between the 2 centre cylinders of each bank and Im wondering if one cylinder is stealing fuel from the other one, so if anyone is designing one of these setups then these are things to look out for. Im now at a point where I have to decide wether to carry on with this or to go for plan B (make a new plenum with a set of 2-4 throttles on the side or front), this would be a lot easier, I would then need to change the TVR trumpets (well they aint trumpets they are scrap metal pipes) for 45mm trumpets.
Phil
Phil
Hi there,
yeah, Im thinking of having another go at it but rather than using the Samco pipe simply get some more tube welded onto the main tube so it no longer will have the steps. Seperate lambda's is a good idea I hadnt thought of, but I got so fed up and just ripped it off and put the plenum back on so I could drive it
Phil
yeah, Im thinking of having another go at it but rather than using the Samco pipe simply get some more tube welded onto the main tube so it no longer will have the steps. Seperate lambda's is a good idea I hadnt thought of, but I got so fed up and just ripped it off and put the plenum back on so I could drive it
Phil
I think Bill Shurvinton has put his finger on the trouble, can't believe I over looked it to be honest 
but its the fact that the 2 centre cylinders of each bank are joined and they are drawing air in from both throttle plates so they will be weaker than the outer 2. Well we are hoping its the trouble any how, so the gap is being welded up this week and Im going to try again the weekend.
I did try Alpha_N but the trouble wasnt that I couldnt tune it, it was that I couldnt get it to tune if you see what I mean
The plan for this is to use MAP untill the pressure is slightly under atmospheric then it will switch over to Alpha, giving me a 24x12 map 
as map is the only real way of tuning for efficiency, and then I can use TPS when I put my foot down.
Sequential may be something that MS3 will address, but Im still not convinced, maybe I need to try it and see what it does for myself.
Phil
but its the fact that the 2 centre cylinders of each bank are joined and they are drawing air in from both throttle plates so they will be weaker than the outer 2. Well we are hoping its the trouble any how, so the gap is being welded up this week and Im going to try again the weekend. I did try Alpha_N but the trouble wasnt that I couldnt tune it, it was that I couldnt get it to tune if you see what I mean
The plan for this is to use MAP untill the pressure is slightly under atmospheric then it will switch over to Alpha, giving me a 24x12 map as map is the only real way of tuning for efficiency, and then I can use TPS when I put my foot down. Sequential may be something that MS3 will address, but Im still not convinced, maybe I need to try it and see what it does for myself.
Phil
Hi there,
as the gap between the centre 2 cylinders on each bank is really tight the tubes were welded together before they were joined to the base, as the welder wouldnt have been able to get in to there to weld wit hthem on the base. This meant that there was a very slight gap between the tubes and the very centre of the base, so whilst they were not leaking to atmosphere they could breath through each others throttle plate. I got the gap welded up internally and re-ground it all down, now it is running really well! Im half way through tuning now and it looks like its cured the problems, I have a very strong idle and its a lot easier to tune. just cant beleive I didnt think of it!!
Phil
as the gap between the centre 2 cylinders on each bank is really tight the tubes were welded together before they were joined to the base, as the welder wouldnt have been able to get in to there to weld wit hthem on the base. This meant that there was a very slight gap between the tubes and the very centre of the base, so whilst they were not leaking to atmosphere they could breath through each others throttle plate. I got the gap welded up internally and re-ground it all down, now it is running really well! Im half way through tuning now and it looks like its cured the problems, I have a very strong idle and its a lot easier to tune. just cant beleive I didnt think of it!!
Phil
Hi there,
well Im still tuning it, but its going really well, Ive been using AutoTune in MT as the VE values are all over the place as the tuned length varies with throttle position. Im definetly going to have to swap from MAP to TPS as the throttle increases, as I run out of map around 20% throttle. So right now Im tuning the lower throttle positions of under atmosphere in the plenum. Then I will start doing the higher throttle positions. I could do it using TPS all the time, but I would like to have some economy from it, so MAP has to be retained for cruising, etc,
Phil
well Im still tuning it, but its going really well, Ive been using AutoTune in MT as the VE values are all over the place as the tuned length varies with throttle position. Im definetly going to have to swap from MAP to TPS as the throttle increases, as I run out of map around 20% throttle. So right now Im tuning the lower throttle positions of under atmosphere in the plenum. Then I will start doing the higher throttle positions. I could do it using TPS all the time, but I would like to have some economy from it, so MAP has to be retained for cruising, etc,
Phil
I gave up 
I simply couldnt get them balanced and tuned at part throttle and overrun, especially overrun. I know of someone else doing it and they are struggling with it all too and have put it on hold till the winter. I was going to have another go but after driving Robs 5.5 with the triple act plenum and talking to Rob Im now convinced this is as good if not better than ITB's. So Im about to cut 2 plenums in half and have 2 throttle intakes, one either side. This is going to be sooo much easier to tune it is untrue, and it should look good too, I hope,
Phil
I simply couldnt get them balanced and tuned at part throttle and overrun, especially overrun. I know of someone else doing it and they are struggling with it all too and have put it on hold till the winter. I was going to have another go but after driving Robs 5.5 with the triple act plenum and talking to Rob Im now convinced this is as good if not better than ITB's. So Im about to cut 2 plenums in half and have 2 throttle intakes, one either side. This is going to be sooo much easier to tune it is untrue, and it should look good too, I hope, Phil
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