Sensible tuning on the 1.6 8v

[Richie-Van-GTi 72 2 Cars]

I'm after some advice and recommendations please.

I have a stock 91 pre cat 1.6 8v, I plan on a full motronic conversion, mp5.2 from a 306 xsi remapped to suit. Since it's getting mapped it makes sense to have the engine built to a better spec and only map once. I planned on a Piper ultimate road cam with similar lift to standard but a lot more duration and a 4 branch manifold to 2 inch stainless system. Also to incorporate a 306 throttle body with the idle air valve built in.

Questions are would it be worth having 3 angle valve seats put in, any recommendations for who and should I skin the head to raise CR or will the duration cause interference if I do that?

[petert 588]

Cutting the seats "properly" is free hp. ie you won't loose anything. You should also ask to hand blend from the seats down into the bowl. ie a mild porting job.

 

Your compression ratio should be matched to your camshaft choice. Thus if choosing the Piper P16BP285, you'd want 11:1. You will have to skim the head significantly to achieve that on a 1.6. Maybe even a thinner head gasket as well. The valves won't hit the piston.

Edited December 26, 2018 by petert

[Richie-Van-GTi 72 2 Cars]

Thanks Peter, a few basic calculations tell me I need to reduce the compressed volume height by 0.81mm , do you know if the standard head has enough meat to take that off? I am sure I seen a post once on here that stateed how much meat is available but can't find it anymore.

[petert 588]

You can remove up to 2mm safely. I can't recall what the standard height is. It was in another post recently. A big skim will require elongating of one of the engine mount holes.

[Tom Fenton 1,542]

If you are going to the extent of fitting the motronic stuff, then it’s a way off standard, so would a 1900 engine not be an easier way to more power using similar methods?

[Richie-Van-GTi 72 2 Cars]

7 hours ago, petert said:

You can remove up to 2mm safely. I can't recall what the standard height is. It was in another post recently. A big skim will require elongating of one of the engine mount holes.

Oversizing the mount won't be an issue, I thought I recalled 2mm being safe.

 

5 hours ago, Tom Fenton said:

If you are going to the extent of fitting the motronic stuff, then it’s a way off standard, so would a 1900 engine not be an easier way to more power using similar methods?

Yes a 1.9 or even a 16v would have been easier and cheaper for a power increase but I wanted to stay 1.6 since it's the original engine that came with the car, also less hassle with DVLA and insurance etc. I am not chasing huge numbers, just making it a little bit more fun and increasing reliability.

Thanks for the help so far, I bought the 282 degree catcam instead of the piper and a billet flywheel for the motronic so just shopping round for the head work now

[petert 588]

Which Catcam?

[DAN@ADRIAN FLUX 1]

Hi.

If you do find you have any issues with your insurance for these modifications then please feel free to drop me a line.

Regards,

Dan.

[Richie-Van-GTi 72 2 Cars]

On 12/28/2018 at 7:32 AM, petert said:

Which Catcam?

4900366, listed as a trackday cam but the car will be a seldom used toy so I can live with it being a bit lumpy round town.

[boldy205 75]

Its a lot of money for not much gain I'd say. I, like many others on here, looked at tuning the 8v, looked at the cost, and stuck a 16v in there. When I did it Mi16s were a lot more plentiful I guess.

 Regarding insurance,  you still need to disclose all modifications, just to be on the safe side .

 

Just my thoughts  

[Richie-Van-GTi 72 2 Cars]

as I have said its not a question of chasing power although getting a few more ponies is a bonus. The main quest is having something reliable which getting rid of the AFM and the dizzy provides. I know a well set up dizzy system is reliable but with all the dizzy and AFM's getting on a bit they are becoming more prone to issues. Also doing this makes the bay a little bit neater.