Turbo or Bodies? - Saxperience

GeorgeNorris · 22nd July 2016, 15:32

So I've got a Mk1.VTS engine to put into my mango and now i'm wondering what is better to do for mainly road use. Either Turboing the saxo from what i can see costs a lot more gets more power and would effectively make the car less road worthy than throttle bodies or the alternative of bodies that would cost less have less power and its also not a turbo. I'm not exactly looking for the "Right" thing to do just interested in what other people would do in my situation where the car has to be used day to day but also you want it to be fast and it will potentially see some time on tracks and also be unique.
Thanks for reading

Chipwizards · 22nd July 2016, 21:00

For everyday use throttle bodies are too noisy. Great for a few days, a week maybe, but soon you'll tire of it. On top of that, day to day it will be slower because the torque is lower than stock up to around 5500 rpm so unless you're tatering it all the time it won't actually GO as well as a standard engine.

Add to that the fact that it's very difficult to get a good air filter in the space available so you're in danger of shortening engine life with dirty air.

That said, if you decide on a turbo then you MUST buy a quality manifold. If you don't it will warp and probably crack after not very long. Quality manifolds are made with steel-alloy that is typically 30% Nickel, so it isn't cheap. Also, aim for very modest power using a suitably sized turbo. If you think you're going to use a 900-million billion horsepower engine daily you're going to be disappointed with a car that drives badly and breaks down. A broken car is never very fast, no matter how much power it once had.

If you want something spectacular that ends in a cloud of smoke, buy some fireworks.

Another option may be to fit a supercharger. John at GMC does Rotrex based kits. There are cars around that have had them on for years and they are still going, so that says something about the engineering of them. The downside with them is that the boost, and thus the torque, rises and engine revs rise so they are generally 'peaky'. However, if you run the blower so that it is geared to be at its absolute maximum rpm when the engine is at its rev limit, then fit a restrictor to the blower inlet so that the mass airflow/pressure ratio relationship 'tracks' through the middle of the high-efficiency island in the compressor map, the boost will come in earlier, but it won't overboost at high rpm because the restrictor prevents it by limiting the mass flow, which limits the boost. That's what we did with the 306GTi-6 Rotrex conversions that Lynx did a few years ago and they worked really well.

The stock ECU can be used for any eventuality, whether it's a single plug or a three plug.

welshpug · 23rd July 2016, 09:24

bodies are fine on a daily.

they only make lots of noise if you open the throttle too far.

craigyt · 23rd July 2016, 10:42

90% of builds on throttle bodies are broken for parts within 12month!

I used my turbo rallye as a daily for 2yrs when it was 180bhp and i loved every second of it but at 250bhp its a bit too much due to the clutch. Other than that id use it all day everyday if i could!

The supercharger is a good shout but tends to use more fuel as its on boost all the time where as you can drive a turbo car off boost

GeorgeNorris · 23rd July 2016, 14:02

Well those are some interesting points, thanks for the advice and ideas!

Chipwizards · 23rd July 2016, 22:13

Quote:

Originally Posted by craigyt

The supercharger is a good shout but tends to use more fuel as its on boost all the time where as you can drive a turbo car off boost

It depends how you configure it Craig.

Chipwizards · 23rd July 2016, 22:19

Quote:

Originally Posted by welshpug

bodies are fine on a daily.

they only make lots of noise if you open the throttle too far.

I have had more than my share of cars on throttle bodies. If you box the intake and route it away down the front then yes, the are livable. Unfortunately that's not easy to do on a 106.

I have used them with open intakes too and I have found them very tiresome very quickly. Maybe it's to do with the kind of roads I have to drive on.

I used James Pickering's GTi-6 for a week or so when we were developing the bodies for that engine and I actually struggled to sleep after driving home in it, and on those engines the intake it at the front of the motor, not right at the top of the bulkhead in yer face, so to speak.

Also, to make a car enjoyable on the road you need torque, and there there is absolutely no contest at all.

KamRacing · 24th July 2016, 10:06

You've got old lol
The sound of throttlebodies is great. I never tired of it as a daily. When hitting the gas pedal it makes a racket but its not so bad really.

Turbo makes more effortless power though and is certainly quieter

Chipwizards · 24th July 2016, 18:36

Quote:

Originally Posted by KamRacing

You've got old lol

No, I was born old. :-)