Mi16 D6c Engine For 205 Rallye Car - What Cams ?

[andy0075 9 1 Cars]

My 205 GTI rallye car needs more bhp and thus it will get an MI16 XU9J4

D6C engine over the winter.

 

engine specs :

 

-engine will be fully rebuilt

-bottom end with 1.9 GTI crankshaft, lightend and balanced flywheel 1.9GTI with 5,2kg

(both out of my 8V race engine with race clutch)

-standard pistons ( cr original is 10,4:1 )

-the valves and valveseats will be machined as shown on a picture at Peter Taylor's webpage

-45er dbilas throttle bodies

-Megasquirt ECU

-exhaust manifold is from an 309 GTI 16V

-Gearbox 1.9 GTI with 5,2 final drive and Quaife LSD.

 

Questions :

 

-What cams can you suggest ? I need good power from 2500-7500rpm and really

good torque for hard accelerating out of sharp corners in second and third gear :-)

I want to use the cams with the original Hydros and springs !

-How much should/can i skim the head ?

-What exhaustpipe diameter should i use ? 60mm ?

 

If someone has such cams to sell please PM me...THANKS

 

regards, Andy

www.peugeot-racing.at.tf

[unariciflocos 49 1 Cars]

I also have an Mi16 powered Rallye that I use as a hillclimb rally car.

 

You can't skim the head, at least not by a sufficient amount. What I did was deck the block and liners by 0.6 mm to get a compression of about 11:1.

 

My engine will be getting a Peter Taylor Stage 2 inlet cam and std. exhaust cam. Unfortunately his site is down at the moment so I can't give you its specs.

 

Exhaust wise, after a bit of reading on here I found that you don't need more than 56mm, mine is 54 internal diameter.

 

Don't forget to increase the capacity of the sump and baffle it properly. I lost two D6Cs to oil surge. I'll weld an extension to the sump to get at least 7 liters of oil in the sump. I don't want to lose another engine.

Edited November 17, 2010 by unariciflocos

[andy0075 9 1 Cars]

I have sent Peter T. a mail two weeks ago but he does not answer it till now.

 

What i can't understand is, that there are so much different cam

profiles on the market and all cames should do nearly the same. When you

take a look at cams from Kent, CatCams, dbilas, Newman for example for sport/rallye use

then the specs are so different in lift and degrees (PeterT's stage II cam even has less lift

than the original cam ) up to 11,5mm lift and they are from 260°-290° and all cams are

sold as perfect rallye cam and they will give you power from 3000-7000rpm and function

with hydros ?!?!?!?

 

I find it extrem difficult to choose the right profile for me out of this huge amount of cams.

 

OILPROBLEM:

How do you increase the sump capacity to 7 liters ?

How should a well buffled sump look like in your eyes ? Do you weld something

on your own or do you buy such a "buffled sump insert" like the one on ebay ?

[DrSarty 90 1 Cars]

In short, I would do business with Peter Taylor. He has been very busy of late, but that's a good sign.

 

I wouldn't agree with Uni about 0.6mm off block and liners*, as Peter himself recommends 0.4mm giving 10.8:1. I wouldn't say Uni is wrong, but I have faith in Peter's recommendation and would need proof that 0.6mm was reliable.

 

*This is not an easy process, as the liners have to be turned to be parallel with the deck. They have to be held correctly before turning down. Peter can advise.

 

I would go with Pete's cams too. DO NOT get hung up on lift being so important! It's like other arguments where one assumes higher or bigger is always best; it isn't.

 

With lift comes more stress on the valve train amongst other things. I would trust Peter and concentrate on decent duration, cam timing and valve overlap to get decent cylinder filling and decent burn and extraction rather than have larger numbers to talk about down the pub.

 

I have a pair of Peter's cams in Australia already that I was going to sell over here, which are ready to go and you could buy them from me at a good price. Pete can send them to you directly saving them a long journey on a plane. It's one stage II for inlet and one stage I for exhaust. You will need mappable management for this combination.

 

Peter can also make possibly the best wetsump available for the price, and there is a live topic on here ATM about it.

 

With the block strengthener (some call it a sump spacer which it isn't) and a decent wet sump you'll have close to 6L if not slightly over which is plenty. Although one of Peter's sump experiments shows an add on which will bump it up even higher.

 

If you'd like the cams let me know, as they are sitting ready to get on a plane, when they could get to you in the next couple of days.

 

I achieved 240bhp (202 ATW) and 196lbft torque from Peter's stage I regrind as inlet and an OE exhaust, so trust me when I say his cam profiles work.

 

You should get a nice engine, but don't get too stuck on high this and big that, when moderation is the secret, as you want reliability and tractability. That'lll help you win races.

Edited November 18, 2010 by DrSarty

[unariciflocos 49 1 Cars]

My engine has not been built yet, I will assemble it as soon as my rebuild parts are shipped. As for wrong or not, I wouldn't know, only time will tell.

 

I tried to follow Peters' advice word for word. "It's a fiddly job to do correctly but definitely worth the results. Even when fitting new forged pistons, I still deck the liners/block to obtain zero deck height, then remove unwanted material from the dome. " I put the crank and pistons in and I measured 0.6 to get the piston deck height to zero.

 

Related to oil control I've picked up a lot of designs of different people on here and I'm going to take the beset ideas from each. The Constella sump baffle seems like a total rip off, since they stole the design from PTS, invested nothing in its development and are maybe selling it at 10 times its production cost. I will make a cardboard model, then cut sheet metal after the model and weld it in. Apart from the spacer to get 6 liters I will also weld a pocket like in this topic: http://forum.205gtidrivers.com/index.php?showtopic=117923 . 7 liters was just a figure of the top of my head, I'll try and increase the capacity by as much as possible. There's only so much oil that the head can hold and I intend to compensate that by increasing sump capacity.

 

DrSarty, my username is Romanian and it translates to "A fluffy hedgehog". I can see how it would be difficult to read or make some sense of for a non Romanian speaker.

[DrSarty 90 1 Cars]

DrSarty, my username is Romanian and it translates to "A fluffy hedgehog".

 

I gathered you were Romanian, but I'd never have guessed in a gazillion years that it would mean that!

 

I have to admire your English though; it's better than that of many Brits on here!

 

Best of luck with the engine OP. Other advice is to fit a plate diff if you're not already planning to, oh and staged injectors too if you choose throttle bodies.

 

Let me know about the cam offer please ASAP.

Edited November 18, 2010 by DrSarty