911t 2.0 hp+ upgrades

[Eporsche69]

I have stock 1969 911t 2.0. I'm looking f to add some more horsepower, without having to replace the whole engine or if there is an option to turbocharge this engine if possible? I do have extra heads and tranny. Please Help.

[Henry Schmidt]

Originally Posted by Eporsche69

I have stock 1969 911t 2.0. I'm looking f to add some more horsepower, without having to replace the whole engine or if there is an option to turbocharge this engine if possible? I do have extra heads and tranny. Please Help.

The 2450 is an engine I have a great deal of experience with.
The last 2 engines I built for my own cars were this configuration.
I like it because it allows you to build pretty cool performance without compromising the case.
If you bore the 69 case out to fit 90mm barrels the spigot that supports the cylinder gets very thin and although it can be reversed, it can be a costly process, in the event the owner wants it completely stock.
The last 2 2450 we built (69T,& 70T) were 70.4 stroke 86mm bore. 9.5:1 compression, 36 mm intake and 35mm exhaust ports with DC 40 (Mod S) cams.
40 mm Webers and twin plug for the WOW appeal.
SSI heater boxes and an M&K sport muffler.
On the dyno they made 182 and 184 at the rear wheels @ around 6800 rpm.
Great engine to drive.
I have since moved away from the M&K muffler because of a strange harmonic at 5K.



This dyno sheet denotes the same spec with DC 62 cams vs Mod "S".

[Eporsche69]

How do you convert to twin plugs?

[Richey]

You posted you wanted more horsepower , so find a counterweighted crankshaft and build a 2.2 liter
S . You will not be disappointed , but use S camshafts for the most fun engine . The Mod S's do not have the zippiness above 5500 rpm . Henry's engine is nice but you wanted horsepower and not
torque so much ?

[Eporsche69]

The most important thing I want out of my engine is it being able zip around corners. Autocross ready!

[Emo993]

Eporsche69, I have a 2.2 E engine with S pistons, DC30 Mod solex cams, 40PMO carbs. This engine just rips from 5000 to 7000 rpm. I auto-cross a lot and hill climbs, the low end torque is a little disappointing, my set up ended up more of a track motor. I would talk to Henry as to building a motor with more torque mid range verses red line. Mark

[john walker's workshop]

Swap the mod S cams in the above engine for a 66 solex grind and you will get your bottom end back.

[GrantsGarage]

I have a 71 2.2 in my 69T. I added SSIs and the new MSD 6A Ultra with Pertronix in the distributor. A noticaeble change in the way it accelerates and improved idle.

[Richey]

Emo993 said he has DC30's not DC40 Mod S's so switching to Solexs will not change much ,
I'm assuming there are other issues .

[Richey]

I had my CD unit refurbished and noticed a positive difference in the running , so is the MSD
really necessary ?

[Richey]

I had my CD unit refurbished and noticed a positive difference in the running , so is the MSD really necessary ?

[Henry Schmidt]

Originally Posted by john walker's workshop

Swap the mod S cams in the above engine for a 66 solex grind and you will get your bottom end back.

I would have to disagree.
The increased compression of my build allows/requires a little more cam than the Solex. (I am a great fan but not for this build)
The increased lift, similar duration numbers and wider lobe center leaves the Mod"S" cam a far better choice. These are small motors that want to breath to run with spirit.
The wider lobe center will
1) Raise torque to higher rpm
2) Reduces maximum torque
3) Broadens power band
4) Decrease chance of engine knock
5) Decrease cranking compression
6) Idle vacuum and quality is improved
7) Valve overlap decreases
8) Increases piston-to-valve clearance
Given the increased volumetric efficiency of the higher lift cam, low end performance numbers are still higher than the Solex given all other things being equal.

Porsche 911 Solex I/E 248/236 242/230 .455"/.414" 97 4.2-4.6 mm

DC 40 "MOD-S" I/E 266/249 259/242 .474"/.440" 102 4.5 mm

[Eporsche69]

Thanks for the input. Now I have lots to think about.

[Dolly P]

For more horsepower on a stock 1969 911T 2.0, you’ve got a few options without a full engine swap. First, improving airflow with a better exhaust, carbs, or even EFI could give you some gains.

[Jeff Alton]

The 69T has carbs and a pretty good exhaust for its displacement. EFI would help a touch.

[Eporsche69]

So if I get DC 40 "MOD-S" I/E 266/249 259/242 .474"/.440" 102 4.5 mm is there anything I would need to change or can I just install these and ready to roll?

[Richey]

I don't think so , just the new camshafts will be somewhat pointless without also enlarging the intake and exhaust ports . 35.5 mm for the intake and 35 for the exhaust - '67S sizes .Your engine already has the larger '67S size valves so porting
would be a relatively easy process and I believe the results would be very satisfactory . I think the '67S engine is really fun but often overlooked , everyone thinks they want something bigger .

[Henry Schmidt]

Originally Posted by Eporsche69

So if I get DC 40 "MOD-S" I/E 266/249 259/242 .474"/.440" 102 4.5 mm is there anything I would need to change or can I just install these and ready to roll?

Mod "S" cams need compression and valve pockets. Small port heads will only effect the high RPM performance. They should perform well into the mid 6000s.
It not a bad idea to upgrade the valve springs for the higher lift cams. Re-jetting the Webers would work but if the carbs are IDTs they can offer some challenges to transition tuning. The early exhaust will support good performance all the way to 260HP.

[BartdeBruijn]

Henry,

I am building the engine you build a few times before and the one you mentioned above.
Only difference I made was I want to add MFI because of the beauty of it. I have a full 2.4S tuned setup.
Only thing I wonder if that will work with the modS cams……?
Do you have any experience there?

Thanks,
Bart

[Henry Schmidt]

Originally Posted by BartdeBruijn

Henry,

I am building the engine you build a few times before and the one you mentioned above.
Only difference I made was I want to add MFI because of the beauty of it. I have a full 2.4S tuned setup.
Only thing I wonder if that will work with the modS cams……?
Do you have any experience there?

Thanks,
Bart

The "Mod S" cams respond very well to the fuel delivery of the 013 "S" MFI pump.
Tuning is required but there is no need to replace/remap the space cam.