Project Turbo Killer

[sonett]

I actually got some real dyno numbers for my 2.1. 8 valve . I didn't actually use the cylinder head I planned because I need to have a cam made to use it. I took a 2.1 bottom end out of 150k parts car, dropped on a mildly port/polished head with dual springs and a cam. I managed to pull 109.10 HP at 5500 rpm, and 111 ft-lb at 4500 rpm. This is at the wheels. Not too disappointed at that, it was afterall a bunch of used parts that I threw together.

Do you have a graph?
The torque on my car is way too low below 3000rpm, we think it could be down to the secondaries being too long, what length are the secondaries on the MSS race header?

[Luke]

I may have a photo of the graph as I was there when Jason had it on the dyno and seem to remember snapping a pic.

Here is the MSS race vs street headers:



From talking with Jack, these were tuned on an engine dyno to best match the characteristics of his street and race cams.

[sonett]

It would be good if you have the pic.
From just making the primaries smaller, bhp and torque did improve, but compared to other engines, such as 8v 1.9 Peugeot 205's with the same cam/bodies/headwork, the torque under 3000rpm is too low.The exhaust manifolds on these engines have around 14'' primaries and 17'' secondaries, so i am looking at reducing the secondaries to around 17''.

[SwedeSport]

Try these.

[Jordan]

Yeah that torque curve looks pretty flat until it starts petering off. I'm sure CIS isn't doing you any favors though. It would be interesting to see a timing graph as well.

[sonett]

Thanks for posting the pics, the torque looks healthier than mine below 3k, i'll shorten the secondaries and see what happens.

[SwedeSport]

I was hoping for better, but as stated it is a hodge podge of used parts, with some new gaskets. The next step is that the CIS has to go! Some form of sidedraft setup, or ITB's. But I think Im gonna favor doing a trans with an LSD before that happens.

I have a mish mash header. Its actually the primaries from the street header, with the secondaries and collector from a race header. I kept the o2 bung since I drive it on the street. I added a second bung in the collector so I can run a wideband sensor.

[Jordan]

I kept the o2 bung since I drive it on the street. I added a second bung in the collector so I can run a wideband sensor.

Where is your bung hole located and how does it perform? I worry that too many bung hole obstructions mess with the airflow characteristics.

[SwedeSport]

the one for the factory o2 is in the V where the primaries for 1-4 merge. and the other one is on top of the collector just in front of the steering rack.

[sonett]

We needed to find out where the power was falling off with this engine, to optimise it's power, so i fitted stiffer valve springs to allow it to rev out to 7600rpm, i also needed to lift the rev limiter to 7600. This engine doesn't know when to let go of it's power, it looks as though it needs to go 8000rpm but at present i'm not prepared to go any further with this engine, it was meant to be a fast road car, but it's just turning into an animal, as you can see from the latest dyno run, it's still hanging on to it's power at 7600rpm, with a bit of a map tweek i'm sure we could get it over 170bhp.

[Geoff]

Awesome! So what is it like to drive? It looks like it should be pretty exciting around 4500.

With the dual valve springs you should be able to rev higher. I've had my B motor up above 8000

[sonett]

Awesome! So what is it like to drive? It looks like it should be pretty exciting around 4500.

With the dual valve springs you should be able to rev higher. I've had my B motor up above 8000

You couldn't ask for a better fast road car, it idles smooth at 1000rpm, you drive it around town just like a standard car and when you want the power it's there. I'll be getting the map tweaked next month, the AFR has moved around a bit because of the change in exhaust and trumpets, plus it wasn't mapped properly above 6800 and it's too rich above this so i'll be losing some power, i hope i can get it above 170bhp.
I don't want it to go to 8k, the standard pistons won't last long at those speeds, the rod and piston weigh in at over 1.6kg which is just ridiculous.
Why did you take your motor to 8k? Where did the power peak?

[Crazyswede]

Awesome! So what is it like to drive? It looks like it should be pretty exciting around 4500.

With the dual valve springs you should be able to rev higher. I've had my B motor up above 8000

You couldn't ask for a better fast road car, it idles smooth at 1000rpm, you drive it around town just like a standard car and when you want the power it's there. I'll be getting the map tweaked next month, the AFR has moved around a bit because of the change in exhaust and trumpets, plus it wasn't mapped properly above 6800 and it's too rich above this so i'll be losing some power, i hope i can get it above 170bhp.
I don't want it to go to 8k, the standard pistons won't last long at those speeds, the rod and piston weigh in at over 1.6kg which is just ridiculous.
Why did you take your motor to 8k? Where did the power peak?

I believe we hit 8000 rpm during the Maine Forest rally back in the summer of 03(?) .....someone downshifted from 4th to 3rd before entering a corner at 70 mph...and that someone wasnt me...car probably bounces around that rpm during some rally crosses too...not your Euro wheel to wheel deals...think autoX on dirt.

[Jordan]

Awesome! So what is it like to drive? It looks like it should be pretty exciting around 4500.

With the dual valve springs you should be able to rev higher. I've had my B motor up above 8000

You couldn't ask for a better fast road car, it idles smooth at 1000rpm, you drive it around town just like a standard car and when you want the power it's there. I'll be getting the map tweaked next month, the AFR has moved around a bit because of the change in exhaust and trumpets, plus it wasn't mapped properly above 6800 and it's too rich above this so i'll be losing some power, i hope i can get it above 170bhp.
I don't want it to go to 8k, the standard pistons won't last long at those speeds, the rod and piston weigh in at over 1.6kg which is just ridiculous.
Why did you take your motor to 8k? Where did the power peak?

The the MSS cam which I think is the one Geoff has, peak power is @ 7500rpm. Cam is rated to 8500rpm.. not sure how the pistons do at that speed...but I may be finding out

[sonett]

To get the most from your engine, you should ideally take the revs about 500rpm past where the revs start to really drop off, this should then put the rev drop back in the power band. If you look at the graph SwedeSport posted there is no need to take this engine to 7000rpm, it makes peak power around 5500rpm and then the power drops off sharply at 6000rpm.
It would be interesting to see a graph with Geoff's MSS race cam.