After some Rail advice
Discussion
Just need a bit of advice for my engine conversion on my rail, it's all different to me so be gentle
I bought a dragster a year ago with the intention of running the Aircooled flat 4 that was fitted to it, but it was in need of a fair bit of work and I've found there quite a bit missing from the motor so have decided to swap motors to a newer watercooled VW engine, which in the long run will be cheaper to maintain and more reliable.
It was around 700hp and ran low 8's, its got a 2 speed powerglide but i have no idea on the gearing insde.
Now since I'm swapping I've realised lots of stuff might need changing, motorplate, torque converter, possibly gearing as to begin with I plan to fit a normally aspirated V6 with gas so about half the power it used to be.
If i need to change Torque Convertor how do I work out what I need?
Someone mentioned I may need a thicker motorplate but need to know what TC I'm running to work it out,
Also how can I work out the gearing, or can I just take it to someone and they can work it out?
The Aircooled flex plate is SFI rated, do I need the new one to be SFI rated, if so where can I get a custom one made as I'm guessing its not gonna be an of the shelf part as its for a VW
Also if there is anything else I might not have thought about do mention, as I hope to get this turned around quick,
I bought a dragster a year ago with the intention of running the Aircooled flat 4 that was fitted to it, but it was in need of a fair bit of work and I've found there quite a bit missing from the motor so have decided to swap motors to a newer watercooled VW engine, which in the long run will be cheaper to maintain and more reliable.
It was around 700hp and ran low 8's, its got a 2 speed powerglide but i have no idea on the gearing insde.
Now since I'm swapping I've realised lots of stuff might need changing, motorplate, torque converter, possibly gearing as to begin with I plan to fit a normally aspirated V6 with gas so about half the power it used to be.
If i need to change Torque Convertor how do I work out what I need?
Someone mentioned I may need a thicker motorplate but need to know what TC I'm running to work it out,
Also how can I work out the gearing, or can I just take it to someone and they can work it out?
The Aircooled flex plate is SFI rated, do I need the new one to be SFI rated, if so where can I get a custom one made as I'm guessing its not gonna be an of the shelf part as its for a VW
Also if there is anything else I might not have thought about do mention, as I hope to get this turned around quick,
MajorLucky said:
If i need to change Torque Convertor how do I work out what I need?
Get you car weighed, get the engine dynoed and take the results to someone that knows about such things. Frosty would be a good place to start. Then apply for a bank loan to buy the one you need, as opposed to one that'll merely do the job :-)Here's what ive done in the past - hope it will help. Im sure many can offer better advice.
First off put your weight / hp into one of the online calculators and see what it suggests is reasonable for your power to weight ratio. I gave it a shot based off your car weighing around 1300lbs and making 350hp. Im guessing that this is flywheel horsepower so we need to estimate how much horsepower you will have at the wheels. Allowing for drive-line losses id guess at 280 hp. It estimated a 9.71 - which I would think would be at around 140mph. If you take 140mph as your golden number you can figure out your gearing for that top end MPH. Decide your maximum engine RPM (where you should be going through the traps), and take that, your tire size and your MPH to another calculator that will figure out what Rear end gear you need to run that MPH. Allow for some slippage from your convertor - say 10%. If your running a glide then that will have a 1:1 top gear. When it comes to torque convertor though your probably best to talk to a trans specialist like Andy Frost - but id have thought something that you'll want a minimum of 2500 stall. A better guesstimate would be to look at where you make your maximum torque.
Calculators are here:
http://www.freewebs.com/soslo/formulas.htm
When it comes to the SFI specs - have a look in the SPRC rule book. I dont have a copy to hand but chances are you will need SFI Flex plate and SFI harmonic balancer to run those numbers,along with SFI Flex Plate shield and SFI Trans Sheild. These are all dated items so if theres already on on the car check the dates. Also do you know if the chassis is tagged? If not I would seriously recommend getting it checked before doing all the work.
First off put your weight / hp into one of the online calculators and see what it suggests is reasonable for your power to weight ratio. I gave it a shot based off your car weighing around 1300lbs and making 350hp. Im guessing that this is flywheel horsepower so we need to estimate how much horsepower you will have at the wheels. Allowing for drive-line losses id guess at 280 hp. It estimated a 9.71 - which I would think would be at around 140mph. If you take 140mph as your golden number you can figure out your gearing for that top end MPH. Decide your maximum engine RPM (where you should be going through the traps), and take that, your tire size and your MPH to another calculator that will figure out what Rear end gear you need to run that MPH. Allow for some slippage from your convertor - say 10%. If your running a glide then that will have a 1:1 top gear. When it comes to torque convertor though your probably best to talk to a trans specialist like Andy Frost - but id have thought something that you'll want a minimum of 2500 stall. A better guesstimate would be to look at where you make your maximum torque.
Calculators are here:
http://www.freewebs.com/soslo/formulas.htm
When it comes to the SFI specs - have a look in the SPRC rule book. I dont have a copy to hand but chances are you will need SFI Flex plate and SFI harmonic balancer to run those numbers,along with SFI Flex Plate shield and SFI Trans Sheild. These are all dated items so if theres already on on the car check the dates. Also do you know if the chassis is tagged? If not I would seriously recommend getting it checked before doing all the work.
Adding to Dorrisdoormouse's (doormice?) advice, you can begin to see how difficult this is to get it right and how expensive it is if you get it wrong. You'll also need to understand the cumulative effect of your cam profile/inlet manifold/fuel supply combination in order to arrive at the mid point of the bell curve where your maximum output will be found. The torque converter/stall speed and gear ratios must enable your car to operate as close as possible to this optimum. If you get it too low then you'll bog off the start line and never get to use the power you are developing (and have paid for dearly). If you get it too high, you'll just have lots of revs and not much "go". Take your time and be careful who you ask for advice.
Id think your chassis should be good to go... Chassis cert length depends upon the tag its gone on, but if it was tagged that fast that recent then you shouldnt have a problem tagging to the slower speed (8.50 or 7.50). I would think you can get an idea by talking with Mark Norton.
Things will be more complicated for you running VW gear - which is your choice and i know you have a passion for all that is VW. Id say its not likely to be easy to get your SFI spec stuff - especially on Water Cooled - seems like some stuff is available for the air cooled engines already. Id expect a premium price as well compared to say a small block chevy.
Things will be more complicated for you running VW gear - which is your choice and i know you have a passion for all that is VW. Id say its not likely to be easy to get your SFI spec stuff - especially on Water Cooled - seems like some stuff is available for the air cooled engines already. Id expect a premium price as well compared to say a small block chevy.
I will add that ive gone the way of running a relatively unusual (ford) combination and paying double for parts gets old real quick when you get a passion for running quicker and quicker. VW parts im sure will be even more expensive so you might want to keep that in mind before you commit. Its 100% your choice and dont think im trying to tell you what to do, but i figured it best to say it up front - in some respects I wish I'd started with a Chevy....
If your doing it in stages you want to make sure where possible that you build for the higher horsepower setup now (strength wise) so you have the growing room... but remember as you want to change these things often it requires changes elsewhere. Torque Convertor would be a good example of something you will need to change as you upgrade. If your back axle or box need changes then build the strength for your future. Otherwise you end up paying out several times.
Been asking the very same questions myself over the last 12 months, although for a VW ABF motor not VR6.
Quicktime in the states do a rwd SFI Bell housing for VAG Engines that's listed on Jegs, only problem being it's for manual transmissions not a glide. I imagine an air shifted Jericho or alike would work well in the small capacity high horsepower turbo application though and if I could afford it that's the route I'd take.
I was going for a motor/adaptor plate that mounts the ABF to my glide and also mounts the starter motor. I'm looking at two ways of doing the crank hub to take up the extra width of the motor plate. Either have a plain hub made to make up the distance, then have a Chevy flexplate drilled to fit the VW crank bolt pattern. Or if possible have the hub made to adapt the VW bolt pattern to standard Chevy bolt pattern so I can just use a stock sfi flexplate. Not so sure if that can be done though.
Torque converter wise I was going to speak to somebody that knows far better than I do (they make my brain hurt).
This is all just theory though, bar having a powerglide and an ABF on the stand that's as far as I've got.
Good luck with it Luke. Really looking forward to when it's out.
Quicktime in the states do a rwd SFI Bell housing for VAG Engines that's listed on Jegs, only problem being it's for manual transmissions not a glide. I imagine an air shifted Jericho or alike would work well in the small capacity high horsepower turbo application though and if I could afford it that's the route I'd take.
I was going for a motor/adaptor plate that mounts the ABF to my glide and also mounts the starter motor. I'm looking at two ways of doing the crank hub to take up the extra width of the motor plate. Either have a plain hub made to make up the distance, then have a Chevy flexplate drilled to fit the VW crank bolt pattern. Or if possible have the hub made to adapt the VW bolt pattern to standard Chevy bolt pattern so I can just use a stock sfi flexplate. Not so sure if that can be done though.
Torque converter wise I was going to speak to somebody that knows far better than I do (they make my brain hurt).
This is all just theory though, bar having a powerglide and an ABF on the stand that's as far as I've got.
Good luck with it Luke. Really looking forward to when it's out.
Edited by hodgy587 on Friday 17th May 14:57
Spencer, that's exactly where we got the idea from, I thought if a pinto can run 11's my setup might get 10's, it's a step up from what I'm running now and the dam thing gets some use.
I will be picking brains at the main event, as I hope to get it done and out within a few months with this basic setup.
I will be picking brains at the main event, as I hope to get it done and out within a few months with this basic setup.
Edited by MajorLucky on Friday 17th May 18:04
Looks like the first convertor is:
http://www.race-mart.com/JW_Performance-JWP-20448-...
However these things are built specific for a combination... it probably wont be any good at all for your new combination. More information here and a lookup guide for more convertor information:
http://www.docstoc.com/docs/106612551/Torque_Conve...
Not sure what the other one is....
http://www.race-mart.com/JW_Performance-JWP-20448-...
However these things are built specific for a combination... it probably wont be any good at all for your new combination. More information here and a lookup guide for more convertor information:
http://www.docstoc.com/docs/106612551/Torque_Conve...
Not sure what the other one is....
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