Throttle body conversion

s0ck · 28 Apr 2006 at 00:13

OK, so we've had the 'how do I turbo my car' threads etc. How do you go about converting your NASP wagon for use with throttle bodies?
Speculation welcome but I'd prefer some facts too

So far, I'm thinking, inlet manifold comes off, TB's/injectors attach to head. The car I've got in mind is the Rover K series which I believe uses a MAP sensor for fuelling, so it will fuel based on manifold pressure but wait, we just removed the manifold!
Also, how is this done for cars with a MAF? Air is sucked in and metered just after the filter but now each 'trumpet' (I think that's the correct term?) so I'm not sure how that would work at all.
After market management... OK, we all know to get the most out of the engine it's always the best route but we aint talking forced induction here so I was thinking, perhaps, uprated the fuel regulator/increase rail pressure slightly to compensate. Perhaps along with injectors/fuel pump. Then, book an hour on a rolling road or someone who has a wideband lambda to make sure the fuelling is right and er, wham bam job done? :confused:

I suspect I've overlooked something major but please feel free to pick holes in my plan! This is possibly going to be my track car btw. It will most likely start life as a Rover Metro 1.4 16v. They're cheap to run/maintain, nice and light for slinging round the track and hopefully, not too hard to release some extra horses.

If you're sitting there thinking, WTF?! then the basis for all this is that the Lotus Exige used the 1.8 K series with throttle bodies and they made good power, circa 200BHP. Obviously, I don't expect anywhere near this performance from a home brew hybrid rust bucket but that's where the inspiration comes from

s0ck · 28 Apr 2006 at 00:58

Well, if nothing else, I might learn a bit more about how engines work

Just found this:

Airflow is not measured, but calculated based upon engine speed and throttle position.

I'm fairly sure they use a TPS sensor by default and seeing how all the throttles would be moving at the same rate, it might just be a case of attaching it to one of the throttles. Would need some kind of compensation for the extra air and I think this is where it might be an idea to increase the rail pressure slightly. Still hunting for more info...

s0ck · 28 Apr 2006 at 01:11

Thanks for the input

I'm more concerned, initially, with just getting it to start and run rather than the performance side of things. With this in mind, I will try and stick with the OE ECU and speed/density, if at all possible. I would hope to use the injectors from the standard car; does the fuel rail attach directly to the injectors and is it metal cast or tubing of some sort? :confused:

Looks like MS can do Alpha-N so that should fit in perfectly with my track car on a budget

PS: I've no idea if any of this is going to work but it sounds like fun.

s0ck · 28 Apr 2006 at 19:06

I think it's fair to say to say this project will never make serious power

The 1.4k has the narrowest ports of all, lowest duration/lift, etc.
Considerations are obtaining a VVC head (same spec as VHPD) and blanking off the VVC mech which immediately kills a chunk of power but going from there with the TB idea should yield considerably more power. I think ultimately, keeping VVC and not going the TB route would give the biggest gains, or perhaps jumping to a forged T16 turbo setup, although I'm trying to avoid turbo, for the track.
Possibilities are endless but my funds are not

s0ck · 28 Apr 2006 at 19:38

Simon said:
Why?

Linear, predictable power and the fact turbo goodies are expensive

s0ck · 28 Apr 2006 at 21:50

ratface said:
Keep the turbo engine above 3000 (where it should be anyway) and it fine for the track, btw T16 is too tall for metro

1.8vvc is cheapest way to 160+ bhp in a metro

Yep, this is in the back of my mind all the time. I think it would be more fun to try throttle bodies though

I suppose I could sell the throttle body setup on when/if I get bored of it.

Simon said:

If you have nothing useful to post, please don't deride my thread. I would have thought it is fairly obvious what I meant. My coupe coming on boost on a roundabout is enough of a handful. I wouldn't like to be in that scenario at track speeds! I'm just trying to keep it simple and most importantly, cheap.

s0ck · 28 Apr 2006 at 22:33

Jonnycoupe said:
Im of the opinion that you not really asking in the right place either, a motors spin off section of a computer forum is unlikely to found as much info as other sites out there.

You're probably right but I still value some of the members opinions who post here, yourself included

Plus, I think I've had some good info here