Throttle Body discussion
Discussion
I have been toying with the idea of getting a bike body set up for my 1600 cc N/A Pug 106 8v. Initial conversations from the manufacturers of TB's are claiming 20hp would be found.
Having had a few discussions with rolling road operators the general opinion is that gains are more likely to be 5hp. Which when you could be spending £1k+ is not a great ROI.
This got me thinking a bit more as my engine currently has 125hp at the fly / 100 at the wheels, and is basically standard bar a bit more compression and the use of a mappable ECU. (Standard for the car is 103 hp)
Therefore if I was to believe the TB's manufacturers my converted engine could have 145hp, however I am more inclined to believe the RR operators and 130 hp.
Therefore my question is - would it be true to say that if you had a bog standard engine ( in good health) a TB conversion could release 20+hp, but that the majority of that power comes from the mapping element rather than the 'mechanical' throttle body element. And conversely if you've done the mapping to your engine, only small gains would be made from throttle bodies. I am assuming that these mods would be to a standard engine.
I have another question about injector flow rates, the bikes bodies seem to be able to flow up to 250cc, whereas my standard injectors flow around 150cc. Logic states to me that I want to be able to flow more fuel with more air, but the RR operators are saying that that's not the case and can in fact cause a whole load of other problems...
Also on that basis, and if the realistic power gain would be 5hp from TB's, what would you do next to generate more power from the engine.
Having had a few discussions with rolling road operators the general opinion is that gains are more likely to be 5hp. Which when you could be spending £1k+ is not a great ROI.
This got me thinking a bit more as my engine currently has 125hp at the fly / 100 at the wheels, and is basically standard bar a bit more compression and the use of a mappable ECU. (Standard for the car is 103 hp)
Therefore if I was to believe the TB's manufacturers my converted engine could have 145hp, however I am more inclined to believe the RR operators and 130 hp.
Therefore my question is - would it be true to say that if you had a bog standard engine ( in good health) a TB conversion could release 20+hp, but that the majority of that power comes from the mapping element rather than the 'mechanical' throttle body element. And conversely if you've done the mapping to your engine, only small gains would be made from throttle bodies. I am assuming that these mods would be to a standard engine.
I have another question about injector flow rates, the bikes bodies seem to be able to flow up to 250cc, whereas my standard injectors flow around 150cc. Logic states to me that I want to be able to flow more fuel with more air, but the RR operators are saying that that's not the case and can in fact cause a whole load of other problems...
Also on that basis, and if the realistic power gain would be 5hp from TB's, what would you do next to generate more power from the engine.
I don't know your engine specifically, but if I recount my experience with mine it is similar.
e36 328, BBTB, ASC delete, and M50 manifold conversion to derestrict the inlet, which is all to do the same as your mods (in a roundabout way) complete with remap etc.
In the case of mine either the inlet derestriction or the remap will give around 20bhp, but together they do not give 40 bhp, they give 25 (ish) it seems to be that the progressive gains get smaller with each stage of modification.
On the subject of your injectors, I would go with what your RR man says as I do know that mine, which are standard, will flow enough to allow me to turbo & nitrous the car with still enough flow in the bank!
On the subject of what to do next, I went the other side of the combustion process & fitted an M3 full exhaust, which has a fully tubular manifold & larger pipes, with another remap to maximise the benefit & got another 10 bhp.
e36 328, BBTB, ASC delete, and M50 manifold conversion to derestrict the inlet, which is all to do the same as your mods (in a roundabout way) complete with remap etc.
In the case of mine either the inlet derestriction or the remap will give around 20bhp, but together they do not give 40 bhp, they give 25 (ish) it seems to be that the progressive gains get smaller with each stage of modification.
On the subject of your injectors, I would go with what your RR man says as I do know that mine, which are standard, will flow enough to allow me to turbo & nitrous the car with still enough flow in the bank!
On the subject of what to do next, I went the other side of the combustion process & fitted an M3 full exhaust, which has a fully tubular manifold & larger pipes, with another remap to maximise the benefit & got another 10 bhp.
Edited by andyiley on Tuesday 18th June 15:26
i can tell you that whilst peak power may not increase massively, power and torque through the rev range will increase considerably. there will be a surge of power lower down that will keep on pulling, as opposed to a gradual build up of power
i can also tell you that the noise of throttle bodies at 7k RPM is enough to create a considerable mess in your trousers
i can also tell you that the noise of throttle bodies at 7k RPM is enough to create a considerable mess in your trousers
I have recently purchase and fitted a new exhaust system from the manifold back. It is virtually a straight thru system 421, with no cat ( as it is a race car). I hadn't bothered to get the car re rolling roaded as for some reason I just assumed that the improvements would be there. Are you saying that I should RR it? I can't see it making any difference?
bertieg said:
i can tell you that whilst peak power may not increase massively, power and torque through the rev range will increase considerably. there will be a surge of power lower down that will keep on pulling, as opposed to a gradual build up of power
i can also tell you that the noise of throttle bodies at 7k RPM is enough to create a considerable mess in your trousers
How can you tell me that?i can also tell you that the noise of throttle bodies at 7k RPM is enough to create a considerable mess in your trousers
I suspect you are confusing a less linear torque output vs throttle pedal angle (due to the larger effective opening area at part throttle) with an actual overall increase in BMEP.
Also, chances are, that the "diy" intake manifold made to accept the throttle bodies will also have a poorer spread of intake dynamics tuning. In effect, boosting torque at only a single engine speed (and reducing it elsewhere, again making the engine feel more "peaky" but actually also making the car slower........)
Max_Torque said:
bertieg said:
i can tell you that whilst peak power may not increase massively, power and torque through the rev range will increase considerably. there will be a surge of power lower down that will keep on pulling, as opposed to a gradual build up of power
i can also tell you that the noise of throttle bodies at 7k RPM is enough to create a considerable mess in your trousers
How can you tell me that?i can also tell you that the noise of throttle bodies at 7k RPM is enough to create a considerable mess in your trousers
I suspect you are confusing a less linear torque output vs throttle pedal angle (due to the larger effective opening area at part throttle) with an actual overall increase in BMEP.
Also, chances are, that the "diy" intake manifold made to accept the throttle bodies will also have a poorer spread of intake dynamics tuning. In effect, boosting torque at only a single engine speed (and reducing it elsewhere, again making the engine feel more "peaky" but actually also making the car slower........)
The gains do seem to be very dependant upon the engine in question.
For an engine such as yours, I would doubt the 20 BHP gain claims, but 10 with a proper re-map doesn't seem unreasonable.
However, for the Mazda KLDE going in my car, switching to ITBs and binning the massive standard inlet releases another 40 bhp with a remap. But the standard inlet isn't great for flow but does give some good harmonic tuning which the ITBs loose. But the gains from them outweigh the loses so you still end up gaining overall.
Also, changing to ITB/bike bodies can be done for very little money, assuming you have a mappable ECU capable of handling them. For my V6 it cost me £75 for all 6 ITBs and another £25 in ally plate to make the direct to head adapters for them. It's time consuming making it all yourself, but certainly no great task if you can accurately mark things out and can tap holes cleanly. Having a pillar drill helps massively with this.
For an engine such as yours, I would doubt the 20 BHP gain claims, but 10 with a proper re-map doesn't seem unreasonable.
However, for the Mazda KLDE going in my car, switching to ITBs and binning the massive standard inlet releases another 40 bhp with a remap. But the standard inlet isn't great for flow but does give some good harmonic tuning which the ITBs loose. But the gains from them outweigh the loses so you still end up gaining overall.
Also, changing to ITB/bike bodies can be done for very little money, assuming you have a mappable ECU capable of handling them. For my V6 it cost me £75 for all 6 ITBs and another £25 in ally plate to make the direct to head adapters for them. It's time consuming making it all yourself, but certainly no great task if you can accurately mark things out and can tap holes cleanly. Having a pillar drill helps massively with this.
doogz said:
What have you done to the engine that it currently produces so much more than standard power?
A camshaft and some sort of remap/standalone management system would be unlikely to release that sort of power from that engine? You say you've just fitted an exhaust? What is it?
Is the inlet currently completely standard?
And is there a reason you're sticking with the 8 valve? It's a race car yes? The 16v is always going to be the better starting point.
the engine is blueprinted. the regs the engine was originally built to only allowed blueprinting. It has had the head skimmed and the compression raised. I suspect that most of the power increase has come from the ECU. Cam is standard, valves reground etc, group N valve springs, a bit of lightening and balancing standard in let, 421 manifold and custom exhaustA camshaft and some sort of remap/standalone management system would be unlikely to release that sort of power from that engine? You say you've just fitted an exhaust? What is it?
Is the inlet currently completely standard?
And is there a reason you're sticking with the 8 valve? It's a race car yes? The 16v is always going to be the better starting point.
It has been RR'd on a few operators roads, Owens gave 127, Millway 125, Motorworx 122. It is also not the most pwoerful of the cars I used to race against within the same class, some were getting 132+ hp.
My latest thinking is to fit an S1 rallye inlet as this would be much cheaper and would yiled very similar gains to a TB set up. I'm sticking with the 8v as it is in good mechanical condition.
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