964T vs 930 engine mod considerations

[pavulon]

What sorts of differences are at issue when considering these two cars?

[vmb]

subscribing. I have a frankenstein (or rather, mutt) of an engine. I have a 965 block/ finned cylinders, but the rest is the original 930 stuff. The IC, headers/turbo weren't replaced if I understand the PO correctly.

[RarlyL8]

The 965 has standard many of the mild upgrades that are performed on the 930 such as the K27-7200 turbo, larger intercooler, and greater boost level. The transaxle should also be considered as it is a 5spd with lower gearing than the 930 4spd.
Typical upgrades for the 965 would be deleting the cats and adding a more free flowing exhaust system and changing out the K27-7200 turbo to a K27S, K27HFS, or some non-K27 brand that can be adapted to fit.
The ignition system on the 965 is also superior to the 930. Electronic controls can be modified.
The fuel systems on the late 930 and 965 3.3L engines are very similar with the WUR being more complicated along with the Lambda system computer or turbo control unit. These are often deleted and optioned with the modified fuel head and adjustable WUR such as the 930.
Basically anything that is done to a 965 can be done to a 930 as the engine platforms are identical. Apparently Porsche had a lot of 930 engines left over in 1990.

[911nut]

Originally Posted by RarlyL8

and greater boost level.

Brian, my understanding is that the 965 had less boost, .7 bar vs .8 for the 930.

[RarlyL8]

I think it is the other way around. By the end of the run C2T3.6 had 0.9bar if memory serves and SC grind cams. I'll need to dig out the manual to verify. All the 3.3L 930's had the same 0.7-0.75bar springs.

[clutch-monkey]

is a K29 turbo too big for a 965 that is mostly stock except for an exhaust and GT2 cams?

[pavulon]

I once drove an otherwise stock '89 930 w/ a k29. It was a bit boggy on the bottom end but really squirted when boost came on and didn't seem to run out of breath near redline. It was fun for the short time I drove it. May or may not be fun every time it was driven.

[clutch-monkey]

thanks it's what i have now, and doesn't make any more power that 270rwhp.. wondering what else needs to be done? i don't know what a standard 930/964 feels like so i have no reference

[RarlyL8]

What exactly do you have? A stock 965 with a K29 bolted on?
If so the K29 is not being fully utilized as the exhaust system will choke it. That is a big laggy turbo to start with, old school race car power band.
The standard 930 is pretty disappointing stock but wakes up quick to any mods done. The standard 965 is much better stock but continues to respond in kind to modification.

[clutch-monkey]

as per the info i got with the car it is apparently a B&B exhaust, GT2 cams (no idea how to verify that) and a K29 S11 turbo (1 bar boost).
sorry pavulon don't mean to hijack it's just been bugging me hopefully the info is useful to others too

[IMONBOOST]

clutch-monkey, you may be down on power and it could be so many things. I would start with a boost gauge so you know the truth about how much boost you are generating, then I would move on to checking your AFRs, they may be way off. Take it easy until you get this data, you can buy an LM-1 or Zeitronix for this, I think this is an invaluable investment for these cars.

pavulon, the best upgrade on both is to make sure the CIS is running right, it took me 2 months of debugging and get everything in corrected. If made a world of difference. Then on the 965 at least, loose the CAT. From here on, there are many options.

[clutch-monkey]

AFR's *should* be fine as it should have been checked and adjusted on the dyno. either way i'll grab a pic of the dyno sheet anyway. is the stock boost guage not to be trusted? will definitely look into getting one.

[IMONBOOST]

965 digital guage is not trustable and will not read more than .7 bar anyways.

[clutch-monkey]

ah ok. mine does read 1 bar (wierd), but is it not supposed to be able to register more than .7?
either way i take your point and will look at aftermarket items.

[pavulon]

Originally Posted by clutch-monkey

sorry pavulon don't mean to hijack it's just been bugging me hopefully the info is useful to others too

No worries. It's all good information!!

[clutch-monkey]

this is my dyno sheet


AFR's look a bit off if i'm reading that right - a bit rich?

[RarlyL8]

You are down on power. The ARFs look typical for old stock WUR. Safe but not optimal. What do you mean by B&B exhaust? Headers, muffler, both? Are you still running a cat? Graph looks like you've got a cork in it.

[911nut]

Originally Posted by RarlyL8

I think it is the other way around. By the end of the run C2T3.6 had 0.9bar if memory serves and SC grind cams. I'll need to dig out the manual to verify. All the 3.3L 930's had the same 0.7-0.75bar springs.

In "Porsche 911 Story", Frere stated that the 930 was .8 bar and the 965 was .7 (the digital boost gauge in the 965 only reads to .7 bar). I'm not sure that is completely factual but I haven't seen many errors in that book. For some reason the factory upped the boost of the 3.6 engine and added hotter cams, as you have stated.

[clutch-monkey]

Originally Posted by RarlyL8

You are down on power. The ARFs look typical for old stock WUR. Safe but not optimal. What do you mean by B&B exhaust? Headers, muffler, both? Are you still running a cat? Graph looks like you've got a cork in it.

i took it to mean full exhaust, not sure on the cats. has external wastegate/screamer pipe which i assume is aftermarket haha..

i took some photo's to see if it that can help. maybe someone can id the turbo visually to verify it is a K29 as the ad stated. if it helps the modifications were allegedly done by penske racing back in the mid 90's




what did the K29 come off originally?

[RarlyL8]

The Porsche 930 factory shop manual specs for WG are 0.70-0.85bar so not much help there.
Typically a good 930 waste gate will be full open by 0.75bar which is why I use that figure.

Looks like you have headers but what about the muffler? If there is still a cat in place it may explain the missing power. Need to see the tag on the turbo to identify, K29 is not stock.