Is It Worth It.(Aftermarket Engine Management On Standard Manifold)

[indreams 0]

Hi all

 

I use my 309 GTI16 for pre-historic rallies and I'm thinking of changing the ECU to a mappeble one like the megasquirt as switching to ITB or carb's is against the regulations in Denmark.

 

I'm planing on changing the inlet filter and remove Air flow meter and thereby changing to a TPS.

 

My question is is it worth doing? I mean is it noticeable?

 

regards

[dcc 855]

Do you have any modifications to the engine?

 

The standard setup, in good trim, is pretty damn good to be fair.

 

You'd also be looking at up to £1000 to gain marginal figures on a standard engine.

 

One benefit though would be a change to the gti6 manifold if permitted. it has trumpets cast internally.

[Tom Fenton 1,542]

My gut feeling is that it would be worthwhile getting rid of the restriction of the air flow meter. However I haven't done it so could be wrong. As above its a fair lump of cash to find out!

[welshpug 1,662]

it was certainly a mod done on challenge cars back in the day.

[indreams 0]

is't an old gr.N car which have other cams and a gr.A exhaust manifold som some mods have been done. I also have an PTS 5-speed gearbox with a max speed of 100 mph fitted to it.

[dcc 855]

then personally yes it would make sense to me to get it mapped to get the best out of the car

[unariciflocos 49 1 Cars]

And while you're at it you may whip off the head and give it a good skim to increase the compression a bit.

[welshpug 1,662]

no need, 309 never got the low comp engine afaik.

[Anthony 1,003]

My gut feeling is that it would be worthwhile getting rid of the restriction of the air flow meter. However I haven't done it so could be wrong. As above its a fair lump of cash to find out!

Can't speak for Mi16 and Motronic, but certainly on a 1.9 8v and Jetronic, there was negligible difference (within 1%) in peak figures between standard management with an AFM and dizzy, and a fully mapped Emerald using TPS for load. Sandy who did the mapping didn't seem particularly surprised that there was no increase in peak figures (driveability and responsiveness were improved though).

 

That said, that Jetronic setup did run VERY well and fuelling on the wideband was very good, so I expect a typical poorly setup example would see improvements but not because the AFM was restrictive.

[unariciflocos 49 1 Cars]

no need, 309 never got the low comp engine afaik.

 

Any engine responds better to higher compression. The OP said it may have cams and if he's going to have it remapped might as well increase the compression, especially since it's so easy to do on an 8 valve.

 

Either way I believe there are gains to be had from aftermarket management.

Edited November 12, 2014 by unariciflocos

[welshpug 1,662]

its not an 8v...

[unariciflocos 49 1 Cars]

Ah, sorry, missed that.

[kyepan 291]

You open the door to other modification possibilities such as longer duration rally cams, and taking advantage of fuelling in areas in the rev range that are responding to exhaust manifold pulse tuning effects.

 

Whilst you won't be able to take advantage of ITBS and the benifits they bring, tuning on a plenum is still a possiblity, and there are some larger throttle bodies (vag) that are a direct fit if you reach an inlet flow restriction.

 

Cheers

J

Edited November 13, 2014 by kyepan

[petert 591]

I'd definitely do it. The AFM is an unnecessary restriction, you will then have more options for ignition solutions and you'll pick up low-midrange torque through better ignition mapping (if you spend the time on the dyno finding it).

[Simes 248 2 Cars]

I binned all of it when I converted my mi16 to a gti6 inlet. It rid me of the old AFM, ignition amp, distributor crap and coil and I also gained 10bhp.

 

I then got bodies a year or so later.

[indreams 0]

Hi all

 

Thanks a lot for all the reply, it has been enlightening

 

I believe that the main advantage would be more low down torque and drivability wish is much needed in rallying.

 

My best friend has an rolling road so no worries regarding mapping.

[welshpug 1,662]

its not a rr you need, its a good mapper !

[indreams 0]

he is that as well, having mapped well above 100 pugs (he's a OMEX dealer)

[GLPoomobile 958]

I've often thought if I had the budget I'd go the same way. But for me, not because of gains or future upgrades, just because of future proofing. With Jetronic/motronic parts wearing out and becoming harder to source I'd rather have a robust setup that is newer and isn't limited by parts availability when things fail.

[dcc 855]

Ant did exactly that iirc with a bog standard 8v!