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 Post subject: How to produce a good DD redblock engine
PostPosted: Sat Oct 24, 2015 11:19 am 
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If you want to pick up more torque(HP doesn't really matter if you're using an auto for daily driving and staying under 4000rpm), you have to up the compression of the engine via a lower duration camshaft or reducing the volume of the compression chamber. Airflow efficiency always helps, too, but you don't want to take it so far that you have good high rpm power and not too much low rpm power. Anything you do to open up the intake and exhaust will help, although not as much as you'd probably hope. While the factory intake manifold may leave a good bit to be desired, the exhaust manifold and downpipe setup are really not that bad. I would not recommend spending much money on the exhaust or intake at this stage in the game. A factory turbo exhaust is plenty for these power levels, and you can convert your airbox's preheat setup into an additional cold air intake, though.

You can keep the auto and a/c, just realize that sometimes when you're going up big hills on the highway, or you want full acceleration power, click the a/c off for those few seconds and then turn it back on after. You'll still get cool air while it's off, as long as it isn't off for too long.

Your camshaft is likely to be your first upgrade. You want something slightly larger than stock, but not with too much more duration, if any more, if you're wanting low end grunt. You can also have a little bit of both worlds if you go with a somewhat mild cam and then use an adjustable cam gear to adjust it to your daily needs.

The T cam is a good camshaft for NA use if you're just using the car as a daily driver and looking for more torque. It was .3s faster in the quarter mile than the original M cam in my old Beige Bomber('87 244 automatic) with everything setup the same way(retarded 4 degrees, tight valve clearances, advanced ignition timing). 17.5 seconds flat vs. 17.8! The T cam will probably produce more power than most other camshafts you put into the car until at least 3,000 rpm(it pulled hard to 5k rpm the way I had it set up in the Beige Bomber). It is also the best camshaft if you're looking for more torque and are not going to to do much else that's discussed in here.

If you want more power above that, you're going to want to get a larger camshaft. B cams are the cheapest upgrade, but idle slightly rougher than the very similar A cam. I'd run an A cam if you can find one because they are slightly more torquey, maybe the best torque/well rounded factory cam. Next up, the V or VX camshaft are more modern grind, with decent lift and low duration, good for emissions and efficiency at lower rpm. These cams will all produce more HP and peak torque than the T or M cams, but they will be at a higher rpm. If you swap in one of these cams, you'll want to use an adjustable cam gear set at 2-4 degrees advanced, depending on where you want your power/torque to be produced. The VX drives much better when it's advanced some, Volvo even came out with the VX3 version, which is already advanced for you.

If you are willing to give up a little performance below 2000-2500rpm for some better pull to 5500-6000rpm, you'll want an even larger camshaft. Search for an IPD Turbo cam, Volvo K or H camshaft to move the power band up higher. The IPD Turbo cam is surprisingly similar to the A cam in power production, and is a more modern grind with good torque everywhere. The K and H are more aggressive, with worse idles and low rpm performance, but more kick at the top of the rpm range. With those in there, you can use your adjustable cam gear(advanced 3-6 degrees) to make the car still have quite decent pep below 2500rpm, but pull hardest from 4500rpm up.

After you've chosen your camshaft, how you set the valve clearances also matters. Tighter valves(.012-.014") make the camshaft seem larger than if you set them looser(.017-.020). The looser you have them, the better the car will perform at low rpm/idle and produce the least emissions. If you're trying to make a tiny cam larger, like the T or factory M cam, then you want to set them tighter, like I did when I was tinkering with the Beige Bomber. A good, normal setup for a daily driver is probably going to be the factory specs of .016-.018". You can also set the intake clearances a little tighter and leave the exhausts a little looser to get a little of both worlds.

How to increase your compression? Put a thin, Cometic MLS headgasket on it and shave the head a little bit. While you're resurfacing the head, you might as well shave it .020 or so and have the valves reground in a good three angle grind. Some port work can be beneficial here as well, but it's something that shouldn't be tinkered with much if you don't know what you're doing. There's not too much to be gained at this level of power production, but it never hurts to clean up any flaws.

Another thing that will help the smoothness and efficiency in general, mostly under 2000rpm and at idle, is upgrade to more modern, 4 hole injectors. These seem to be relatively drop in for the LH2.2 and LH2.4 cars. You can get the full yellow, plastic body injectors from an 850 or S/V70(-98) non-turbo, or get the full pink, plastic body injectors from a 99-?? non-turbo S80. The Yellow ones are slightly smaller or the same flow rate as the stock LH injectors, but the Pink ones are slightly larger. They're both drop in and go. LH2.2 might benefit from some AMM tuning if you can, but LH2.4 will adapt just fine.

Also, don't forget about your tuning. On LH2.2, you really only need to mess with twisting the distributor for more ignition timing. What a good setting is will depend on which camshaft and what your compression is. LH2.4 people can't do much unless they get chips that adjust the ignition timing and main fuel maps. I can do custom chips, but my free time is very low and it's not a priority for me. I can say, that LH2.4 cars have a dead spot off the line that is annoying as heck that can be removed pretty easily with a tune... They go super lean at high load below 2000rpm which makes for a bog feeling if you just step on it off the line sometimes. At least, it was really noticeable in my '91 244 when it was an automatic.

If you are experiencing some detonation while driving with your fuel octane, cam and compression of choice, you can try reducing your ignition timing and/or running tighter intake valve clearance. The tighter clearance will reduce your dynamic compression ratio slightly by increasing the duration/time that the intake valve is open.

Depending on what you do, you'll end up with something that probably has between 10-40HP more than stock("114hp") and 10-30 more lb-ft of torque, with a larger powerband spread of torque/power than stock. Roughly guesstimating from my past experiences/experiments/dynos.

That's all for now, folks.

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 Post subject: Re: How to produce a good DD redblock engine
PostPosted: Sat Oct 24, 2015 12:14 pm 
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Location: Rushing Lane, Scappoose.
Kyle I put a 92 740 motor in this 88 245 with m47. I'm running from JR an ignition chip, the race one with no rev limit. Stock 951 ECU with stock chip. Premium gas. Oh I swapped it out to LH 2.4 of course. Stock M cam I guess. I'm thinking about swapping in one of these A cams I got. Full IPD suspension, rear 23mm bar, bilstein socks. Front has 25mm bar, new KYB struts, upper lower IPD strut braces.

Want to race?

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1984 245 D24 M46.
1990 745 b230FT M46, 13c, 3.73Locker, A-cam, 510K.
1991 744 93 B230, 2.5L 16v, Banks Sidewinder turbo, No sunroof stock, headliner and plastic gone, getrag, twin disc, 3.31 1041K.
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 Post subject: Re: How to produce a good DD redblock engine
PostPosted: Sat Oct 24, 2015 5:32 pm 
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sbabbs wrote:
Want to race?

Sure! It'll have to be next year, though. I don't have time to go to the track before it closes! Working on the General Leif to get it ready for the race at the end of the month.

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