Scott at Team Harco

From another thread - there are ways to get more from the modest 2.5 NA engine without dumping buckets of money.

Hopefully this thread will come through with some ideas on how to get there. All I have to offer is a less restrictive air filter (such as K&N) and a less restrictive exhaust. I'm sure porting the head is a good idea too.

Your turn...

968to986

My brother installed a different throttle cam on his 924S and likes the results. Cheap and sharpens up throttle response. I believe Lindsey Racing makes a chip for the NA cars, which would probably add a little power for a few hundred bucks. An 8v NA with 180hp would be fun (that’s stock 911 SC territory). As a 951 owner, I actually find NA cars very rewarding and challenging to drive fast so a little more power would make one even more fun. Which is sort of the operative word; you not going to win any drag races or scare your passengers, but you’ll have a good time. When people talk about tuning a car for more power, the HP numbers are the talking points, but a nicely tuned motor can feel more alive and responsive which makes driving it more visceral, thereby more fun, in a way that can belie the 15-20% power gains.

Scott at Team Harco

Right - the throttle cam is a good little add. It does not actually improve performance, it just allows the throttle to open quicker with less pedal travel.

180 HP would be real nice. I doubt that is achievable without throwing a lot of money at it. I hope to be proven wrong.

harveyf

Interesting that you bring this up, as I was on the phone last night with Michael Mount getting ideas for a 2.5 litre NA. As usual, I'll offer up many words on my blog as this project gets implemented but here is the short list:
1. Convert fuel management system to Megasquirt, including active wide band air-fuel management $1500
2. Individual throttle bodies $1500 with self fabrication of manifolds
3. A hotter cam $800
4. Michael's secret head porting recipe ???
5. Upgraded outer valve springs $500
6. Headers $1500
7. Low restriction exhaust $500
These dollar values are purely educated guesses.
A quality engine rebuild, which is really the first thing that should be done, can easily run $3000.
Getting more power out of the 2.5 NA will never make economic sense
The cheapest way to make the car accelerate faster is to put the driver on a diet!

I'm making no predictions on power but it will be hard to sneak in at 1 am

chrsvo

I’m currently in the process of doing:
1. conversion to VEMS
2. Camshaft, currently looking at „web cam inc.“ #274 (if I wouldn’t have to pass emissions I’d go for something hotter with 951 valve springs)
3. offset woodruff key for the cam or adjustable pulley
4. Bosch Blue coil plus new NGK plugs and new ignition wiring (this doesn’t necessarily add power. But old coils/wires/plugs definitely loose power)
5. Dansk exhaust and 200 cell cat
6. Possibly 1:10.9 compression?

This should get me to 180 hp.
If I port the head and convert to 2.7 valves, maybe 190hp.
Beyond that, it seems there’s only top end power to be found, so even hotter cam, balance/lighten the cranking stuff and rev higher.
And/or sleeve and bore to 3.0l

Scott at Team Harco

OK - the last two posts have great information. But - I will go out on a limb here: they're outside the "no buckets of money" limitation.

For purposes of talking points - let's put some dollar constraints on this exercise. What can we get for $1000? $2500?

Maybe the above posts could assign approximate costs of the upgrades?

mikseymono

Chipping in.....the best mod is probably to educate the driver and get a course of driving lessons.........the problem with wanting more more power is that a bit more is never enough.......sub $500 I think you will struggle to gain much hp...I think deep down we all know that..so just enjoy your +30/40 year old classic car for what it is.......or save up for a higher spec Porsche.....928 maybe? Would love to be proved wrong though.......

wildcat077

Oh boy ... it all comes down to speed costs money , how fast you wanna go ???
I think Harvey can agree with me on this one ... lol

Won't get into details but approx 10K for a solid reliable engine is not unreasonable !

Scott at Team Harco

Good advice. But I've been racing for more than 35 years and have a pretty good track record. I also instruct other drivers.

The only reason I started this thread was to see if I could yank the chain of a particular member to offer up his tips. Still waiting for his arrival...

Scott at Team Harco

Thanks for the updates, Harvey.

I've always found it a lot easier to take weight out of the car, than the driver...
Sometimes rules get in the way of that.

jderimig

+20HP has been dyno documented with standalone, AFM delete and offset cam key. Easily under $1500.
Lower end expense, NATune + offset cam key , $800
Upper end. VEM's + offset cam key, $1500 (but more tunability).
But as said in an earlier post, the drivability and response belies that numeric value.

With the standalone, do not discount a wet nitrous system. Easy, safe, 200HP for ~$500. However not street legal in most states.
With VEMs or Microsquirt you can use progressive nitrous and you can "dial-a-torque-curve'.

T&T Racing

1.The Lindsey Racing

NA-TUNE MASS AIR FLOW INTAKE KIT 944 8v. ,

eliminates restrictive AFM and replaces with MAF.
is estimated to yield up to 15 hp, Cost from LR is $510.,

2. Find a set of 1988, 10.6 CR, pistons should add 5 HP, Cost is maybe $400.

3. Mill the head to minumum thickness and port the head should add 5 HP, cost is $600.

4. Purchase Jon Milledge camshaft, adjusts for camshaft changes because head thickness is less than stock should add 10+ HP. Cost is $850.

My 2 cents proposal.

HF could verify with Micheal Mount

mikseymono

Fair enough...good luck! I like the look of the Lindsey Racing addons.....I guess the main problem we have is the base price of our blocks are quite low compared to say ...gulp....a 911T......our cars need to double in value, so all the bolt on additions seem better value...proportionately!

harveyf

I just want to add that anything that improves engine breathing is probably a waste without having the ability to revise the air/fuel map under hard throttle. So you get into the $$$ pretty quickly. Maybe we should just go back to the V8 thread

I didn't want to throw any gas on an already burning fire but I was tempted to start a new thread entitled "Merlin Rolls Royce" .

Scott at Team Harco

Great information. Item #1 looks like good bang for the buck. Have a friend that won the kit and free installation at 944Fest a few years ago. He likes it. He's not a racer, so his impression has to be taken as such.

I'll have to confess, I will definitely consider many of these ideas when I finally get around to building my all-conquering 944 RallyCross car. ....it's only been 'in the works' for about 5 years...

So far, I've taken a bunch of weight out of it....