172 cup manifold mods

[timdog]

After reading a thread on here last week about the inlet manifold, i decided to take it off at the weekend. I found the quality to be pretty poor being unfinished cast aluminium.
The pictures below show the manifold where it meets the inlet port. There is a big step as can be seen with the inlet port being the thin scribed line in the middle of the blue. I matched the manifold at both ends and also matched the other part of the manifold not shown and blended this into the throttle body where there was another slight step.
The car has not been dyno'd but seat of the pants the pickup is much improved from just before 3000 revs to about 5000 revs. It also revs out much better and hits the rev limiter before any noticeable drop off in power like before. The car also runs smoother below 2000 revs when the engine is cold where it would lurch along before almost unsure how to fuel itself.
A nice cheap mod for a gain you can feel. Just thought i'd share it.

 

[EVOgone]

Can not see the pics, can you repost..!

 

[timdog]

My ISP is playing up this morning. Try a refresh as it appears to be working now.

 

[Nik]

Good work! The difference is pretty shocking really when you look at it like that. Seems like inlet manifold work is about the best thing you can do to a RenaultSport engine without throwing thousands at it.

 

[seacombe2379]

can you just run through what you did to the inlet manifold did you get it polished off

 

[Phill1978]

dont GDI do this stuff for £150 and decent gains (dependant) 8-12 hp !

to get some power on a 172 it seems 4-2-1 = 10, Inlet,outlet = 10, Induction,Decat(s.cat) = 5-6, mapped together with Rsport = 25 = realistically 190hp + cams for the magic 200/205 with mapping.

apart from cams all of that stuff i.e inlet, decat, induction, Rsport (with bbpt`s swap) can be done for under £700 ! for at least 185`ish on a 172 (with usual 168) good gains, just add 182 exhaust manifold for 192/195`ish

not as expensive now people know how to get best power for pound

 

[EVOgone]

Who does a de-cat to connect a 182 manifold to a 172 system..??

Not a sports cat just a sileced de-cat (costs) etc..?

 

[Gary G]

Charlie at ProSpeed?

 

[Bandit]

is the manifold work something most people can do at home? any chance you can do a quick guide i.e. what you did and tools needed etc.?

cheers

 

[Neil G]

Interested too in what's required to do the work and how long it takes.

 

[timdog]

can you just run through what you did to the inlet manifold did you get it polished off

It all needs to come off the car, then you need to mark it up to see where the problems are.
No polishing, waste of time.

is the manifold work something most people can do at home? any chance you can do a quick guide i.e. what you did and tools needed etc.?

Yes. See above. I used a die grinder. You need an aluminium chip carbide bit and then some sort of sanding rolls or spiral band to finish it off.

Interested too in what's required to do the work and how long it takes.

Took me about 3 hours including marking up and refitting. I do this for a living though so would take a lot longer if its your first time.

 

[EVOgone]

Where are you based ? You can do mine for me..!

 

[BenR]

Tim, if you dont mind me asking. Who do you work for?

 

[timdog]

Not at all. I run my own business building racebike engines. Just feeling like tinkering with my car as its a bit gay running stock when you are a tuner!

 

[BenR]

its cool, got your pm

running stock is gay, but when do we find time to even change our stock air filters....or get the tracking done lol

 

[ant]

18370 posts.

where does the time go!

 

[Guy]

how did you 'scribe' the engineering blue to show the lines for the head ports?? did you creat a template?
or did you just use the gasket as a template?

 

[Andy GDI]

how did you 'scribe' the engineering blue to show the lines for the head ports?? did you creat a template?
or did you just use the gasket as a template?

trade secrets!!!!! ;-)

 

[Guy]

make a template using the bolt holes and pins as locating points

 

[BenR]

how did you 'scribe' the engineering blue to show the lines for the head ports?? did you creat a template?
or did you just use the gasket as a template?

gasket lined up, blued, and a scribe to scratch the blue area.

 

[Andy GDI]

guy... i was joking mate!

 

[Guy]

lol

so the gaskets are actually true to the cylinder head ports and can be used as a template/reference.. wow, its french and something fits.. im amazed. lol

from previous experience the gaskets have never really given a mega accurate representation to the ports..

 

[timdog]

lol

so the gaskets are actually true to the cylinder head ports and can be used as a template/reference.. wow, its french and something fits.. im amazed. lol

from previous experience the gaskets have never really given a mega accurate representation to the ports..

They were very close on mine on the inlet. You will see how good when you take it all off and know then whether or not it will work this way.

 

[Andy GDI]

well close enough to be usable for that....

they are pretty good 95% of the time, I am sure ben will agree... as I have seen him do LOADS of them... at one point they were in a stack on the side of his bench

 

[BenR]

lol

so the gaskets are actually true to the cylinder head ports and can be used as a template/reference.. wow, its french and something fits.. im amazed. lol

from previous experience the gaskets have never really given a mega accurate representation to the ports..

yup, they are very accuratelt made steel gaskets, none of this paper crap, so they are stamped.

They are slightly bigger than the ports, but this is why i leave a 20 thou smaller step so people fitting it, or anomaly ports dont introduce a leading edge step.

 

[-Make-]

it would be nice to see what kind of result this mod will add, in dyno-papers i mean.

btw. how tight those bolts are screwed in manifold (in Nm) ? i cant find that information on dialogys

 

[Guy]

 

[-Make-]

thanks !

maybe i do this mod this spring..

 

[timdog]

Just a quick note to add: The fuel consumption has improved by just over 2mpg with this mod. I do the same journey all the time and mpg never changes. Computer was reset the other day and its definately got better.

 

[-Make-]

timdog (or any one): possible to show few pics of that modded part?

 

[jbCUP]

WICKED done a bit of diy porting on minis in the past - gonna have a go at this at the weekend!

Cheers Guy s for the data sheet ^^^ got it saved.

 

[EVOgone]

Is the Hill power manifold mod and GDI manifold mod the same...?

 

[RichMcc]

Excellent work mate. Ive been thinking of doing this myself, I just had the top of my manifold off to polish the outside of it and to inspected the ports a little closer for this mod.

I cant make my mind up if I should just whip out the grinder and port it myself or go the full hogger and ask ben to chop it open and port it all out.


Any idea of the gain difference between a simple port matched manifold and a reflowed one?

p.s where the heck do you get the blue stuff from Ive been trying to find it lol?

 

[timdog]

You can just use a marker pen instead of engineers blue

 

[hoperacing]

who do you tune bike engines for tim dog?
do you do anything with drag racing?

 

[Gary G]

You should see some of Ben's before and afters....awesome!

 

[-Make-]

Gary G: see what? ..show it

 

[Fred@BTM]

You should see some of Ben's before and afters....awesome!

eewwwwww!!! no thanks!!! and besides, he'll always be ugly, EVEN if he's dressed up

 

[-Make-]

Do those (marked area) have a same kind of step to 'upper' inlet manifold?
..also, 'upper' is with bigger ports?

 

[BenR]

THere is a miss match, its not quite the same thing as the casting ends there and its not always machined flat. But the whole inlet track should be modified from plenham to head.