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Sat Jul 16, 2011 6:17 pm

Hey guys new to the site. I'm building a motor for my sandrail and I have a few questions. I'm starting off with the 1800cc and Im going to be shooting for 400whp on premium pump gas. So here are the questions, Can I lower the compression ratio even lower to say 5:1 so the motor wont detonate at the boost levels I'm wanting to run. Also would you recommend going with a Aftermarket cam or just using higher lift rockers? And lastly what would you say is the stock hp limit for the stock crank?

Thanks,
-Austin

Sat Jul 16, 2011 6:20 pm

400 HP huh? Ummm, what's yer budget there? You aren't going to make 400 on premium pump gas. You won't make 400 with a stock cam and ratio rockers no matter how much boost you throw at it. The stock crank is good for about 60 HP, the way VW designed it. How much boost are you figuring on running?

Sat Jul 16, 2011 6:32 pm

400hp christ! 200 is a hell of a lot enough. A mild 2110 with 5-7psi boost can easily do that and more. And it will be a nice reliable turbo.engine. My 2276 is carbuerated and I probably get over 180. 400 will be a beast to try to control.

Sat Jul 16, 2011 6:32 pm

alr3802 wrote: Hey guys new to the site. Im building a motor for my sandrail and i have a few questions. Im starting off with the 1800cc and Im going to be shooting for 400whp on premium pump gas. So here the questions, Can I lower the compression ratio even lower to say 5:1 so the motor wont detonate at the boost levels im wanting to run. Also Would you recommend going with a Aftermarket cam or just using higher lift rockers? And lastly what would you say is the stock hp limit for the crank?

Thanks,
-Austin

1st off....welcome to the Samba.
Try to take these answers the right way.

1. 400whp is huge.
2. 400hp on the stock crank is impossible.
3. 5 to 1 compression won't keep you out of detonation on pump gas if you actually got near 400whp because you'll need about 40psi of boost.
4. the heads will lift off the block before you get to 400whp and you'd need the 6 stud head mods.
5. 1800cc and 400whp is a grenade if you ever got it there.That is 1/4 mile race only territory with every round tear downs.
6. Never going to see it with a stock cam or stock heads. Boost is not the end all be all of under equipped and under built engines.

Not trying to rain on your parade at all....your expectations for a small aircooled engine need to be adjusted is all.
There are some great guys here with tons of turbo experience that can help you out toward a good build and realistic expectations for your rail.
Kind of sounds like you're just starting out and a turbo motor isn't always the best place to cut your teeth. I've been building engines for eons and I haven't built a turbo engine YET! Not that I'm not weilling......just hasn't been requested. :D

RC

Sat Jul 16, 2011 6:59 pm

My budget is about $5000 its a street rail so I want to be able to run pump gas but I dont want to have to run a water/meth injection system. What I was planning on doing was lowering compression and building it much like a NA motor to where it wouldnt take much boost to reach the power level I'm shooting for. I'm going to be using a gt35r turbo and a Megasquirt management system so I though that because I can run an intercooler the air intake temps should be low enough to be safe on 93 octane. My engine build is looking like this-

-Mahle std bore high performance cylinders and Forged pistons
-I now know I'll need a Scat forged crank
-Scat forged connecting rods
-Scat Split Port Heads
-Melling High volume oil pump
-Scat windage tray
-Scat hi-rev Lifters
-Manton cut to length pushrods
-Large 2nd generation Mazda Rx7 oil cooler
-Scat stocker plus cam w/ Dual Valve springs and retainers kit
-Clevite Bi-Metal bearings
-Custom exhaust manifold
-12H x24w ebay intercooler
-Megasquirt II management
-Rc 800cc injectors
-Aluminum Charge tubes

Thats all I've thought of to this point. Please feel free to inform me of any gaps that you see in the build.

Thanks,
-Austin

Sorry if it looks like I didnt listen I was writing all that^ while everyone else replied I was answering the first post. After all that what would you say is a realistic goal for this motor? Built to what I have above?
Thanks for the great advice i am just getting started on air cooled VWs I normally mess with the Mitsubishi 4g63
Thanks again,
-Austin

Sat Jul 16, 2011 7:24 pm

So you're just an "Aircooled" noob.....
Those Mitsu's build great power and pretty reliably too. Don't expect those levels in a reliable VW engine. Help yourself by building large to start with....stay away from the 1800 size. Go 2110cc at least but I'd go to 2332. 300hp is easily achievable with that size engine and a turbo. That is just a shot across the bow for starters. Water cooled and aircooled are really different animals. Using a big cooler and intercooler is a step in the right direction but you HAVE TO REALLY pay attention to the air cooling system and I mean it's critical for what you want to do no matter what level of boost you end up with. HP is heat....the more of it the more heat and the Aircooled engine can only dissipate so much for so long. Think newer stronger Aluminum block for reliability and strength but they run a bit hotter than the Mag cases. Watch your torque specs at high HP levels as well. All this can be covered later as you get deeper into the real project.

RC

Sat Jul 16, 2011 8:35 pm

Austin, no offense here but to put it bluntly, 400 HP with $5,000 on 93 octane gas is not going to happen. If you are indeed serious about building a 400 or even 300 HP turbo motor I would recommend you call and talk to someone who knows how to achieve that kind of performance from a VW based engine. Marty Staggs will tell it like it is and you can see if it's a project you are truly willing to undertake. My 2 bits.

http://m-specmotorsports.com/

Sat Jul 16, 2011 8:47 pm

Since this is a rail, do yourself a favor and scrap the aircooled idea altogether. Get yourself a Honda K-series, an Ecotec, a Duratec, a Subaru, or some other type of watercooled 4-banger. An engine out of a WRX STI will be turbocharged and have 300HP on pump gas, 100% stock.

Sat Jul 16, 2011 9:30 pm

it's realistic to expect maybe 180 NA or 300 on boost if you really do it right, use the good parts

above that you are into the zone of we don't know what will break :lol:

Sat Jul 16, 2011 9:39 pm

Additionally, scat split port heads have heat issues based on its design. im pretty sure no one uses it in the circuits. They rather use component heads, autocraft, dominators or similiar. With those type, of heads and square like ports you arent going to be drivong it on the street.

Sat Jul 16, 2011 9:51 pm

GT35R is way to big for a 1800cc motor with a 6k rev limit. That turbo won't even spool for any kind of powerband at all. I use those turbos for 2.8l motor.
It can work on a 1.8 liter motor but won't even start to make power until 5-6K+rpm.
Basically you are talking "import tuner" talk,but VW aircools do not fall into the DSM/Honda/VW H20 categories,they are low revving air cooled motors with ineffecient combustion chamber/head design,not to mention weak cases (stock).
I have built 445whp 2.0l street turbo VW's but that was on C16 with 28psi boost. Max on 92 pump was 350-ish whp. That was with 8.2:1 compression/4 valve head,etc. That was a easy 11K + build,with Pauter rods/IC setup/stand alone/etc.,etc.........5k you can build a grenade or a good 150hp motor.
I can build water cooled,not aircooled,so I havce Chico building me a engine right now,it will be around 4K,so I would check him out.
Damn man you have a sandrail,alln you need is 150hp,lol!

Sat Jul 16, 2011 9:58 pm

In schweden is a 400hp 1641cc on E85 at 6800rpm with 2,1bar of boost. And on stock crank, stock valvesizes.

Sun Jul 17, 2011 3:52 am

$5000 might sound like a nice budget, and depending on what you already have it may be. But when you actually start buying all the individual components it really goes quickly. I have about $7000 in my NA 2110 and that is all parts and machining, as I did the assembly myself. Of course I started with nothing and bought every single nut, bolt and component to make it happen. $5000 just doesn't sound like enough to build a reliable turbo engine to me, but then I've never built one before either.
Damn, I could have built a pretty nice blown big block Chevy for what I have in my little four banger. :roll:

Sun Jul 17, 2011 4:05 am

jfats808 wrote: Additionally, scat split port heads have heat issues based on its design. im pretty sure no one uses it in the circuits. They rather use component heads, autocraft, dominators or similiar. With those type, of heads and square like ports you arent going to be drivong it on the street.

I have never had heat issues with 101mm split ports on the street.

Sun Jul 17, 2011 5:53 am

Whats your budget for a transaxle for a 400 horse motor?

Casey

Sun Jul 17, 2011 6:04 am

earthquake wrote: Whats your budget for a transaxle for a 400 horse motor?

Casey Very astute question Casey.........

RC

Sun Jul 17, 2011 7:03 am

better be about the same as the buget he set for his engine... :wink:

Sun Jul 17, 2011 9:47 am

Thanks guys for the wake up call guys. I just thought it was capable of a bit more from reading Hotvws magazine. Im just now starting to see how crzy 400hp in a rail would be. I took a ride in a buddys this morning and its was nuts i asked him what he did to the motor and all he has is dual webers and a header. So since I'm now well informed realistically how much could I make with 2500. (I completely forgot to include the transmission my budget is shrinking fast :cry: ) Im am definately a noob when it comes to aircooled vws. I have thought of just using a 4g63 with a 1st gen FWD trans but i dont want to have to deal with all of the cooling system and other issues that come up if that engine gets caught in the elements.

Thanks,
-Austin

Sun Jul 17, 2011 9:55 am

alr3802 wrote: So since I'm now well informed realistically how much could I make with 2500.
Assuming you mean $2,500, that would get you a very nice rebuilt stock 1600 with a header and some Kadrons. About 70-75 HP.

alr3802 wrote: I have thought of just using a 4g63 with a 1st gen FWD trans
I have no idea what that is - it's Greek to me. :shock:

Sun Jul 17, 2011 10:19 am

The 4g63 is the engine that was found in the 1st generaton eclipses there were NA and turbo versions. It is a very strong engine people have only upgraded the fuel system and the turbo and where able to make 500hp on the stock internals. Since all 1st gen eclipses turbo or not had a 4g63 the FWD transmission from a non turbo standard 1st gen will bolt right up to a turbo motor. I lowered my budget to get a bus transaxle but i dont think I'll need $2500 to buy one. I think that I could find a good bus transaxle for $1000. Anyway after riding in that rail I think that Dual webers and header are all i need right now. I might do Bigger bore cylinders later if the powerbug starts to bite. The reason for going to turbo was not only for the power but the sound I guess its from being an Import guy but i love the sound of a turbo engine at full song. 8)

Thanks,
-Austin