If i was going to put together an old 1.8 8-valve engine on the cheap, meaning not spending $600 for fancy connecting rods, how high could I regularly wind it out without getting to look at the inside of the block without tools? That's the kind of crap that made me jump to rotaries.

Good rod bolts would be in use. So will a decent cam (open for suggestions) and 12:1 compression or so.

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Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.



Edited 1 time(s). Last edit at 10/10/2010 04:09PM by Pete.

You're not going to run an 8v very high without solid lifters a nasty cam and some port work, I ran a 16v with a factory bottom end at 7700-7900 rpm consistently on CIS, but it had a bunch of head work done. rod bolts should keep you covered to 8500-8800....I'd go with a solid lifter head an a 300+ degree cam to make power up top.....better have a good gear box that will keep you up there, carbs would be good too since CIS is good for factory stuff and thats just about it.

What are you doing with it?

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-Tom
DemonRallyTeam | Fine Tuning | CTS Turbo & RP Turbos | RalleyTuned | JRM | Meister Autowerks
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Edited 1 time(s). Last edit at 10/10/2010 05:30PM by Tom B.

Consider running an ABA 2.0 block with an old solid lifter head cam and the factory fuel system for the car. the ABA has a better torque curve, better oiling. mill the head down add a cam valve springs. not sure how high you could rev the motor, that would be up to the cam.
An ABF conversion while a bit more pricey would be the best bang for the buck.

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Tom B

What are you doing with it?

Rallycross. I'd like to have a decent RPM buffer about 1500rpm higher than the top of the powerband to prevent exploding the engine over dusty spots.

I kind of did that to the LATEST 13B that I killed. (I lost count, was that #3 or #4 this year?) Was seeing 8500-9000rpm on the straights and the engine was gaining some revs when leaving the ground or hitting dusty spots. I don't know for certain if the excess revs did the engine in or if it was dust.

Independent throttles are definitely part of the plan. The stock intake sucks immensely. I have enough counterflow intakes that I feel comfortable with hitting them with a bandsaw and adapting... something. 48mm throttles from LT1 engines look promisingly inexpensive.

Thing that sucks is, I finally got the chassis setup for the RX-7 *nailed*.



Edited 1 time(s). Last edit at 10/10/2010 07:54PM by Pete.

ok, my friend, you need gearing, its rally-x, you shouldn't need the most powerful motor in the world, you need traction and gearing to make your motor work for you, that and a rev limiter to avoid breaking stuff.

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-Tom
DemonRallyTeam | Fine Tuning | CTS Turbo & RP Turbos | RalleyTuned | JRM | Meister Autowerks
Spitfire EFI | Product Apparel | JVAB Imports | NLS | AP Tuning | USRT

Add us on Facebook | Next Event: 2013 Olympus Rally June 22-23 Olympia, WA

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Tom B
ok, my friend, you need gearing, its rally-x, you shouldn't need the most powerful motor in the world,

Well... the way I figure it, I do more with my cars than just rallycross, so I want to have fun.

I found 200hp to be the magic number for the Mazda. I'm probably not going to be able to make nearly as much power or torque with the VW engine, but I'm okay with that. I just want to do the inexpensive stuff (independent throttles, 1.8t pistons, nice cam) and avoid the expensive stuff.

I do have everything needed to put an Audi K24 on the Corrado G60 block sitting here, as well, but I haven't had good luck with forced induction cars. Plus torque makes for breakage.

They only way to ever find out where used rods will fail is to run them till they do.

As best as I can tell trying to filter the bull from the wisdom, stock rods with good bolts are good for high 7k's all day long.

I can understand skipping a shift by reving the piss out of it even if it is not making much power up there when the next turn is only 3 seconds away like in Rally X - even on stock CIS.

Thanks, Derek. Filtering the bull from the wisdom is why I asked here - I figure, most of the people on VW forums are either drag racers or road racers. You can get away with a lot of mistakes on the dragstrip, and road racers seem to be at either extreme of engine build - either high dollar aftermarket everything, or "rules sez it has to all be OEM, and this OEM cam lets it pull to 5800!"

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derek
As best as I can tell trying to filter the bull from the wisdom, stock rods with good bolts are good for high 7k's all day long.

That's my understanding (and to some extent experience) as well.
Apparently you need to change the bearings a bit often though, once you get near 8K. Only heard that from one guy though - but he is quite knowledgeable.

My 16V (which uses same crap as 8V) is using stock rods, pistons, crank, yada yada yada - all stock bottom end, and no machining done to any of that.
I'm running to 7500 or so, and have been for two years... no weird sound there... only issues are the cam followers that tend to rattle a bit at idle after a particular hard run. But then again, they may very easily have covered 100K miles, and though I changed the oilpump to a new one, I can forgive the followers for having issues :-).

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Brgrds
Brian

1.8L 8v's are a dime a dozen for nearly no cost (you see freebies on vortex occasionally). I'd spend what cash you have on a getting a good head prepped (at least a valve job, resurfacing, fresh springs, lifters, and a cam) and then just consider the bottom ends disposable. I honestly doubt you will break them. I routinely ran my 1.8L (and later an early ABA bottom end with the same 1.8L head) in the 7000 range with not much of a problem, using a TT 276 hydraulic cam. This is definitely not the best power available but it was very solid (I made 104 on the same dyno that my 45mm ITB'd 9A 16v made 136 at the wheels).

I broke valve springs occasionally was my only engine related failures. That could have been avoided if I just replaced the springs every few events.

I would highly suggest the programmable EFI route - those 8v's REALLY wake up with a proper map. Megasquirt (verson 2.2 or 3.0 PCB with a MS1 ECU - running the squirt and spark extra code) is great for a budget build, and Tom and I both have rally experience with that setup (it is a little sensitive to the vibrations of rally out of the box but it is easily solved).

I have some really solid 8V maps for MS that I would gladly share if you wanted to go that route. It takes next to no effort to integrate it with a digifant car. It's a little more complicated converting a CIS car (just because of the way the fuel lines are set up and if you have a vacuum advance dizzy you need to change it to the digifant fixed window one) but it's still very doable.

Plus you don't even need the newer fancier megasquirt, since you just use the 4-window hall trigger on the distributor as the crank position sensor.

You could expect to spend something like $150-200 for the ECU kit (meaning you'd have to assemble it yourself), $50 for a wiring harness pigtail, another $50 for a throttle body with a TPS (passat 16v auto, california digifant MK2's, there's a few places to easily get them) and maybe another $50 on a 40w iron from radio shack, a couple spare tips, some solder and some heat shrink. Maybe another $100 on a set of 24# injectors or an adjustable FPR (if you have a digifant car they have 19# @ 3-bar stock injectors).

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cblakely
. Megasquirt (verson 2.2 or 3.0 PCB with a MS1 ECU - running the squirt and spark extra code) is great for a budget build, and Tom and I both have rally experience with that setup (it is a little sensitive to the vibrations of rally out of the box but it is easily solved).

THREADJACK!

sorry to change the subject, but I have been curious about using a MS for the rallycar, what kind of tricks did you do to beef it up?

ditch anything that can come loose or have an intermittent connection due to vibrations, and be very sure you did a good job soldering. A loose joint might cause something like one of your injector driver banks to stop firing intermittently. "Why am I pinging!??!"

I soldered the ECU directly to the board (got rid of the socket), glued down with hot glue all the small parts (caps and the crystal clock gen), and then mounted the ECU with some rubber isolator studs. Worked great after that.

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alkun

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cblakely
. Megasquirt (verson 2.2 or 3.0 PCB with a MS1 ECU - running the squirt and spark extra code) is great for a budget build, and Tom and I both have rally experience with that setup (it is a little sensitive to the vibrations of rally out of the box but it is easily solved).

THREADJACK!

sorry to change the subject, but I have been curious about using a MS for the rallycar, what kind of tricks did you do to beef it up?

Why anyone would spend $500 and several weeks (both conservative estimates) of their spare time to make a rally car LESS reliable while only gaining 6-8hp is beyond me. It seems buying a used 2.0L bottom end would be money and time much much better spent.

Or, better yet, get yourself a 16v and I have everything upstream from the head sitting in a storage bin for a screaming price. Intake manifold, TB, intake boot, airbox & fuel distributor...

Oh - yeah - MegaSquirt is definitely going to be there. I have two boxes and the RX-7 has been 'squirted since 2007. I love it.

One of my competitors is in a Golf - as far as I know, it's a stock Digifant-II engine, like the Golf street car I had - and his car pulls waaaay harder than mine ever did. Especially at the top end. On the other hand, his car is maybe 1800lb, which helps.

Of course, I'm leaning more and more towards the spinny turbo thingy. It'd be neat to have a 10-valve turbo in one car and an 8-valve turbo in the other. I'd mostly be re-using the bits from when the one engine was supercharged (they sell cheeep chips for turbo conversions) and leftover bits from the Audi turbo engines I'd been collecting.

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Josh Wimpey

Or, better yet, get yourself a 16v and I have everything upstream from the head sitting in a storage bin for a screaming price. Intake manifold, TB, intake boot, airbox & fuel distributor...

Would these bits make it easier to put a CIS 16v engine from an '88 into a '97 (2.0 ABA OE)?