Throttle Body recommendations

CalLookVWs · Post by **CalLookVWs** » Mon Feb 02, 2009 8:43 am

Well, I just sold my 48 DHLA side draft, and I'll be going EFI. Quite a few people have recommended me to go with Megasquirt. The car will be making 450HP at boost (28-30psi) before a 75 shot of nitrous, which I will add at a later date. The motor is a 78.8 X 94 - 2187cc motor. This car will also be street driven. I'm just starting to read on the EFI stuff, and to be honest, I'm still pretty lost. Luckily, I have a friend that's built MS and is going to help along the way with tuning etc.

Any thoughts on which throttle body I should run (brand, size, application etc.)? I've heard Mustang 5.0 or maybe a BBK high performance version for the same car? Money is no object....If I can't afford it, I'll just save up longer. I want the best stuff that will perform and last.

MinamiKotaro · Post by **MinamiKotaro** » Mon Feb 02, 2009 8:59 am

Either dual 48mm TBs or a 65mm Ford TB on a properly designed plenum would be good.

CalLookVWs · Post by **CalLookVWs** » Mon Feb 02, 2009 9:29 am

65? See, that's why I asked. I figured that since I had a 48mm side draft (dual throat) that I had to be in the neighborhood of 96mm. Another "basic" question....Should I mount the trottle body before or after the turbo?

Ryan Brill · Post by **Ryan Brill** » Mon Feb 02, 2009 2:29 pm

No.....You need to figure out the area which is pi r^2. The 65 will out flow a dual throat 48.

SUbuggy · Post by **SUbuggy** » Mon Feb 02, 2009 3:20 pm

if you are going forced induction, TB size is not nearly as critical is normally aspirated.

Money is no object....If I can't afford it, I'll just save up longer. I want the best stuff that will perform and last.

if money is really no object, and you are going "all out" why screw around with a low budget EFI system? There are so many really good systems out there...................spend all that effort on other things rather than tinkering with a finicky DIY efi system.

Mark the canuck · Post by **Mark the canuck** » Mon Feb 02, 2009 3:45 pm

Early 90's honda preludes also have a 65mm TB

CalLookVWs · Post by **CalLookVWs** » Mon Feb 02, 2009 6:14 pm

SUbuggy wrote:if you are going forced induction, TB size is not nearly as critical is normally aspirated.

Money is no object....If I can't afford it, I'll just save up longer. I want the best stuff that will perform and last.
if money is really no object, and you are going "all out" why screw around with a low budget EFI system? There are so many really good systems out there...................spend all that effort on other things rather than tinkering with a finicky DIY efi system.

I'm just learning (literally started to read up a little bit this weekend). I've had a lot of people recommend the Megasquirt setup. I see that Marty is selling Haltech stuff...but like I said, I'm just learning and completely ignorant to EFI. At this point, I know what multi port is, what a throttle body is, and that EFI needs more fuel pressure than a carb setup. That's about it! Ofcourse, I'm building a high HP turbo motor and I don't want a cheesy setup...but I don't know of what all it out there. I know that I don't like the CB setup with twin 48mm TB's. I want a single TB, and may end up intercooling the motor instead of nitrous. I'm in NO hurry to finish this car. If it takes me another 2 years, I really don't care. I have other cars to play with. I feel like a 5 year old kid, having his dad tell him to go adjust his IDA's for him.....A complete sponge

MinamiKotaro · Post by **MinamiKotaro** » Mon Feb 02, 2009 6:24 pm

SUbuggy wrote:if money is really no object, and you are going "all out" why screw around with a low budget EFI system? There are so many really good systems out there...................spend all that effort on other things rather than tinkering with a finicky DIY efi system.

There are drag cars running 6s on MS, just fyi.

SUbuggy · Post by **SUbuggy** » Mon Feb 02, 2009 10:04 pm

[/quote]There are drag cars running 6s on MS, just fyi.

I don't doubt that, and I never said MS is a POS.

What I am saying is that MS is not a great system for a novice, or aren't a whiz at electronics. If you WANT to spend a lot of time soldering on boards, screwing around with code and never ending updates, or rock bottom price is your thing, than great go for it. But if you can afford to buy an off the shelf top notch rock solid stable system, than I don't understand why you wouldn't.

I also understand someone is now selling a MS in some sort of completed form, even a plug-n-play, but have olny worked on one system.

As long as we are on here tlaking about MS, can someone tell me on their latest and greatest ECU (MS2?)

how many injector drivers does it have?

any impedance or are you limited in injector selection? what sort of compensations does it have for a given injector?

how many ignition outputs does it have, can you "dwell map" your coils?

what is the resolution of the trigger input? (many ECU's will read 60-2, but IGNORE most of the teeth and only make engine position calculations based on one tooth per cylinder)

will it do drive by wire?

does it offer any knock control?

closed loop boost feedback?

just wondering. thanks

Mark the canuck · Post by **Mark the canuck** » Tue Feb 03, 2009 3:40 am

CalLookVWs wrote: I'm just learning (literally started to read up a little bit this weekend).

I use SDS, even if you decide on a different system their tech pages have a lot of info, do your homework before you jump in.
Here's their site, links to their tech pages are at the bottom of the home page.

http://www.sdsefi.com/

Theo · Post by **Theo** » Tue Feb 03, 2009 11:50 am

In my opinion, building a Megasquirt and a simulator board and then installing it into a car is like going to Fuel Injection University. I learned so much from the MS site and all of the community. If you want to understand FI at a practical level you cannot do better.

2 cents

Theo

raygreenwood · Post by **raygreenwood** » Tue Feb 03, 2009 2:58 pm

Except by learning to work on the most basic forms of injection...like D-jet and CIS. Injection is actually only partially about the electronics. Its just as much (if not more) about manifolds, intakes and TB's. Ray

Theo · Post by **Theo** » Tue Feb 03, 2009 5:41 pm

Perhaps that’s true Ray. I still think that building the MS a function at a time and then testing that function is an incredible learning experience. Converting the motor, setting up the fuel system and wiring the whole thing and getting it to start is quite and accomplishment. The biggest problem I had was the fuel system.

I never thought about building manifold or intakes but focused on what I could purchase for a reasonable amount of $

CalLookVW:
I went with the Mexi system partly because I could afford it and it seemed to be really well designed. I love the look of it.

I have a US version too and I didn't use it because I think it looks crappy. The pregnant generator stand... But rumor is it will make more power than the Mexi system.

For big drag race power I would be tempted to use the dual throttle bodies.

Lots of people seem to have good luck with the Ford 5.0 TB. I found the stock ones are easy to find. Lots of aftermarket options for the same fitment.

For a 450 hp motor I would look at the stuff Turbo Bob has shown us and I think Marty Staggs gives good no nonsense advice.

bj · Post by bj » Tue Feb 03, 2009 9:54 pm

i am new to the VW scene as well and have started reading up on FI.

SDS has a lot of useful information (whether you buy their stuff or not), MS has a TON of information as well as well as forum support.

what i did was just google around and soak up what i could on the subject.

i had a blast reading this site: http://www.dune-buggy.com/turbo/

this was one of the first things i read about FI. i thought i was pretty informative for a beginner like me.

good luck with the build.

bj

MRRAGPICKER · Post by **MRRAGPICKER** » Wed Feb 11, 2009 5:00 pm

Mark the canuck you have a PM.