05 Apr Gains from ITBs on a Clio
We all know they look awesome and sound epic, but what gains will you actually see from a set of throttle bodies when fitting them to your car?
To find out, I took my “frankenstein” Phase 1 Clio 172 with 197 engine along to Mtec Automotive in Westbury.
The process was as follows:
First I put the car onto the rollers and I mapped it to find out how much power it would make, then the car came off the Rollers, and Lesley took the Individual Throttle Bodies off and replaced them with a standard (all be it port matched) 197 inlet instead, then it went back onto the rollers, I mapped it again so that we had a back to back set of figures from the same car on the same day at the same rollers mapped by the same person, so every variable was taken care of.
Then just cause at CSOC we like to be thorough, I nitrous’ed the car and did it again, you know, just because!
Power figures in ascending order:
Standard 197 inlet : 178 BHP
ITB inlet : 194 BHP
Standard inlet + nitrous : 210BHP (and a whopping 200lbft of torque)
So we gained a very healthy 16 BHP on the identical engine, with no other changes than just the swap of the inlet manifold, that’s a pretty healthy gain by any standards.
And with the nitrous, we gained exactly double what we did with the throttle bodies, 32bhp.
NOTES
Details of test car: The test car is a 172 clio, fitted with a 197 engine and gearbox.
The management is aftermarket and the dephasor solenoid is controlled on/off like a 172 rather than variable like on a 197 with closed loop feedback, and it runs a 172 exhaust manifold, so its essentially a halfway house between the 172 engine and a 197 engine so dont take too much number of exact figures in terms of it being either a 172 or a 197 engine, the key thing is the difference that JUST an inlet swap makes with every other variable being the same.
About the Rollers : With regards to figures from the Mtec Automotive Dyno Dynamics rolling road in my experience a normal healthy 172 on this particuarly honest set of rollers will generally make in the 160s, a 197 will generally make in the 180s. Obviously there are other rolling roads out there where cars will make 20bhp more than that but its no good comparing figures from a different set of rollers.
