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FAST 102mm vs FAST 92mm

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Old 03-11-2016, 08:41 AM
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Default FAST 102mm vs FAST 92mm

Okay, I'm ordering a FAST intake before the end of the month to take advantage of the deal Vengeance Racing has going on, which includes free porting for either the FAST 102mm intake or the FAST 92mm intake. I'm really on the fence about which one to order. My setup consists of the following:

Dart/RHS CNC'd 223cc heads from Advanced Induction
227/235 110LSA cam
LS6 intake
1 3/4 Stainless Works Long Tube Headers
Texas Speed True Duals (dumped)
Accel 44 lb/hr injectors
SLP lid
No MAF (SD Tuned)

This setup is begging for a FAST intake. The heads flow extremely well, and the LS6 intake is just not cutting it. I know the FAST 102mm intake will make more power than the FAST 92mm intake, but how much more is the question. The advantage of the FAST 92mm intake is it's ability to basically be bolted on and ran without the need for any modifications to the intake, or having to purchase aftermarket fuel rails. Another advantage is my current injectors will fit without having to do any grinding to the intake. I don't mind dealing with some of the headaches I'll have with the FAST 102 if there is going to be a significant increase in performance over the FAST 92. So, has anyone switched from a FAST 92 to a FAST 102 and seen some significant increases? I'm all ears here guys. Anyone who wants to chime in with their opinion is welcome.
Old 03-11-2016, 08:46 AM
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I was actually thinking about this exact thing this morning for when I do my heads. I myself was thinking about doing the 92mm and putting the extra money that would be needed to get the 102 to work towards some bigger primary headers because IMO I'd need a 104 or whatever it is FTP lid, and bigger maf like the Texas Speed 102 I think it is (I have a 90mm zo6 maf already) to optimize the Fast 102. But you have a SD tune so the MAF doesn't apply to you.
Old 03-11-2016, 09:25 AM
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Given your combo I would lean towards the Fast 102 just so your aren't kicking yourself down the road.

However the difference would likely be in the 8-10 rwhp range at peak, maybe a tad higher on a really good day but I wouldn't hold my breath. So it depends if the trouble is worth it for that amount.
Old 03-11-2016, 09:53 AM
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Well, on Vengeance's website, the FAST 102mm intake is cheaper than the FAST 92mm intake. After buying some e-bay aftermarket rails (which I've read work really good), it'd be a wash. I know I'll have to relocate the MAP, which requires adding a fitting to the FAST 102mm intake, and others have done this and posted pictures, so it's not a huge deal, but just something extra you have to do to make the FAST 102mm intake work. I also know I'll have to do some grinding on the water pump, but again, not too big of a deal. If you think I'd see 8 to 10 more HP out of the FAST 102mm intake, then I think that's worth it. It's not like I'm going from another FAST intake to the 102, so there isn't going to be that additional cost.
Old 03-11-2016, 10:04 AM
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I think that is a reasonable expectation based on results online. I've been tempted to upgrade myself but just not enough to pull the trigger.

I wouldn't recommend it if your heads weren't so potent, but I think you would see some gains and I'm sure down the road you will be looking at more cubes which is where it will really shine over the 92.
Old 03-11-2016, 10:24 AM
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Originally Posted by thunderstruck507
I think that is a reasonable expectation based on results online. I've been tempted to upgrade myself but just not enough to pull the trigger.

I wouldn't recommend it if your heads weren't so potent, but I think you would see some gains and I'm sure down the road you will be looking at more cubes which is where it will really shine over the 92.
I've been telling myself to just do it right the first time and go the FAST 102mm route, but finding out exactly what I'm going to need to make it work has been kind of sketch. I know my current injectors are not going to fit without doing some grinding on the intake. How much grinding will be needed, I won't know until I get it, but it may be better off for me to sell the current injectors and find some similar ones that are the thin/pencil style.
Old 03-11-2016, 10:43 AM
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You don't HAVE to relocate the map. It will rotate 90 degrees so the connector points up. You just use a large fender washer to hold it.
Old 03-11-2016, 10:48 AM
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Originally Posted by Darth_V8r
You don't HAVE to relocate the map. It will rotate 90 degrees so the connector points up. You just use a large fender washer to hold it.
That's good to know. Appreciate the information.
Old 03-11-2016, 11:02 PM
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Why aftermarket rails? I bought take-off LS2 rails which fit it better from Scoggin Dickey. I think I paid like $95.

Then you can either use LS3 injectors with a spacer, a spacer kit on the rails for LS1 (which FAST sells for like $30 - your best bet), or LS2 sized injectors which are plug and play (best option if you ever decide you want some ID1000s down the road for a turbo...).

You may have to grind the water pump. You'll need a longer brake booster hose. And you'll need to clearance your firewall for the MAP or relocate it. I just relocated it and it makes it easier to troubleshoot since you can get to it easy.

Oh and last thing. The FAST is a piece of **** in terms of build quality and fit and finish. Atrocious garbage. Try to figure out a way to get the bolts to stay. With blue loctite they still come loose, and I end up with vacuum leaks through the shell of the top and bottom. Whee!
Old 03-12-2016, 08:25 AM
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Either way you are gonna get a big bump in power. Benefits of the 92 are bolt right on with existing rails, injectors, no spacers, reuse stock bellow, no moving or mod to map sensor. Benefits of the 102 are better construction and better design. Also the possibility of gaining 5-10hp over the 92.
Old 03-12-2016, 09:01 AM
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Originally Posted by Rise of the Phoenix
I've been telling myself to just do it right the first time and go the FAST 102mm route, but finding out exactly what I'm going to need to make it work has been kind of sketch. I know my current injectors are not going to fit without doing some grinding on the intake. How much grinding will be needed, I won't know until I get it, but it may be better off for me to sell the current injectors and find some similar ones that are the thin/pencil style.
People make a fast 102 swap way more complicated than it needs to be really. First off as darth said you can rotate the map with a fender washer, another option is just putting it on the front of the manifold like the later style. I have heard of some small issues with that but I ran it like that and never had an issue. I also ran in it in the back and used a small fitting tapped into the intake.This was my favorite way, mainly because there was no chance of bad readings (not that I ever had any in the front) and I could put a small piece of hose to extend the map out to make it easy to remove. I dont favor the fender washer method because unlike the other 2 methods you will still need to remove the intake if you have an issue with the map.

Now on to injectors. What I say here will apply only to ls2/3 fuel rails. FAST rails have kits you order in accordance with what injectors you're going to use. The fast billet rails are a waste of money unless you want the looks. LS2/3 rails are cheap and work great. I bought mine for 40 bucks off of corvetteforum.

I highly recommend you sell the "fat" injectors. In the end they offer no real fuel advantage over any other style and if you ever had to sell the intake, not many people will want one thats been grinded on. Ls3/ls7 injector can be had very cheap (100-120 a set) and they flow 42lb. From there you will need the appropriate spacers and ev1-ev6 electrical connectors. Another option is using pontiac gtp injectors which will have the ev1 connector you need already on them, they are also the same height as ls1 stock injectors and they also flow 42lb. Pm screen name MIKE MORRIS on here, he usually has a few sets he sells for about 100 bucks.

The type of injector you go with will determine what spacer you need. Now IF you go with an injector that needs a spacer on it then be sure to get spacers from FIC not FAST. The FIC adapters sit on TOP of the injectors while FAST and other brands sit between the injectors and the intake. These are a horrible design because it spaces the injector up and out of the port disrupting the flow pattern.

The rules are as follows with stock LS2/3 rails.

Stock LS1 "height" injectors (gtp) will need a washer spacer kit that mounts between the rails and the manifold to space the rails up off the intake as ls1 injectors are taller than what the intake was designed for.

LS3/LS7/LSA/LS9 "height" are shorter than what the intake was designed for and will need fuel injector spacers that mount on top of the injector so they will reach the fuel rails. The rails will bolt right to the intake. These injectors also use ev6 connectors so adapters will be needed.

LS2 "height" these inejectors are what the intake was designed for and other than possibly needing an ev6-ev1 adapter plug everything will bolt right up. Stock ls2 injectors are only 33lb though so aftermarket ones would be needed.
Old 03-12-2016, 10:40 AM
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8-10 hp. If you're making the swap anyway then I would do it.

The 102 really only has an advantage on a full sausage heads \cam build
Old 03-12-2016, 10:59 AM
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Originally Posted by redbird555
People make a fast 102 swap way more complicated than it needs to be really. First off as darth said you can rotate the map with a fender washer, another option is just putting it on the front of the manifold like the later style. I have heard of some small issues with that but I ran it like that and never had an issue. I also ran in it in the back and used a small fitting tapped into the intake.This was my favorite way, mainly because there was no chance of bad readings (not that I ever had any in the front) and I could put a small piece of hose to extend the map out to make it easy to remove. I dont favor the fender washer method because unlike the other 2 methods you will still need to remove the intake if you have an issue with the map.

Now on to injectors. What I say here will apply only to ls2/3 fuel rails. FAST rails have kits you order in accordance with what injectors you're going to use. The fast billet rails are a waste of money unless you want the looks. LS2/3 rails are cheap and work great. I bought mine for 40 bucks off of corvetteforum.

I highly recommend you sell the "fat" injectors. In the end they offer no real fuel advantage over any other style and if you ever had to sell the intake, not many people will want one thats been grinded on. Ls3/ls7 injector can be had very cheap (100-120 a set) and they flow 42lb. From there you will need the appropriate spacers and ev1-ev6 electrical connectors. Another option is using pontiac gtp injectors which will have the ev1 connector you need already on them, they are also the same height as ls1 stock injectors and they also flow 42lb. Pm screen name MIKE MORRIS on here, he usually has a few sets he sells for about 100 bucks.

The type of injector you go with will determine what spacer you need. Now IF you go with an injector that needs a spacer on it then be sure to get spacers from FIC not FAST. The FIC adapters sit on TOP of the injectors while FAST and other brands sit between the injectors and the intake. These are a horrible design because it spaces the injector up and out of the port disrupting the flow pattern.

The rules are as follows with stock LS2/3 rails.

Stock LS1 "height" injectors (gtp) will need a washer spacer kit that mounts between the rails and the manifold to space the rails up off the intake as ls1 injectors are taller than what the intake was designed for.

LS3/LS7/LSA/LS9 "height" are shorter than what the intake was designed for and will need fuel injector spacers that mount on top of the injector so they will reach the fuel rails. The rails will bolt right to the intake. These injectors also use ev6 connectors so adapters will be needed.

LS2 "height" these inejectors are what the intake was designed for and other than possibly needing an ev6-ev1 adapter plug everything will bolt right up. Stock ls2 injectors are only 33lb though so aftermarket ones would be needed.
Damn good information, and I thank you a lot for sharing. This will really help me with making a decision on injectors. I'm thinking about getting some 80lb injectors because I'll eventually add a D1SC to the combo. Someone was telling me you can get some 80lb injectors for pretty cheap. Can't remember what brand the guy said they were, but I'm thinking it was Siemens.
Old 03-12-2016, 01:08 PM
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You could do that idk how expensive Siemens ones are but I can't imagine any 80lb injector being cheap lol
Old 03-12-2016, 08:27 PM
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Here are a few pics of my 102 install. It wasn't fun by any means. Aftermarket rails with the spacer kit, map extension harness and a LS 6 valley cover to clean things up.
Attached Thumbnails FAST 102mm vs FAST 92mm-img_20160312_152316950.jpg   FAST 102mm vs FAST 92mm-img_20160312_152321834.jpg   FAST 102mm vs FAST 92mm-img_20151204_172129172.jpg   FAST 102mm vs FAST 92mm-img_20160210_180521744.jpg   FAST 102mm vs FAST 92mm-img_20160310_243548731.jpg  

Old 03-12-2016, 08:57 PM
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I went back and forth myself on this one. In the end, the what...10 rwhp would be better spent finishing up any suspension work or finishing my nitrous setup. I ended up getting a ported 92 for 650$ without the extra 2-300$ of additional stuff needed for the 102 when I could get better bang for my buck spending that elsewhere.
Old 03-13-2016, 10:06 AM
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Originally Posted by Whisper
I went back and forth myself on this one. In the end, the what...10 rwhp would be better spent finishing up any suspension work or finishing my nitrous setup. I ended up getting a ported 92 for 650$ without the extra 2-300$ of additional stuff needed for the 102 when I could get better bang for my buck spending that elsewhere.
This is my same idea, spend the extra money elsewhere.
Old 03-13-2016, 10:27 AM
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Wish I didn't just do an LS6 intake, the ported 92 sounds really tempting. Maybe I should just get one and hide it away until the eventual engine rebuild.
Old 03-14-2016, 10:03 AM
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Originally Posted by JakeFusion
Why aftermarket rails? I bought take-off LS2 rails which fit it better from Scoggin Dickey. I think I paid like $95.

Then you can either use LS3 injectors with a spacer, a spacer kit on the rails for LS1 (which FAST sells for like $30 - your best bet), or LS2 sized injectors which are plug and play (best option if you ever decide you want some ID1000s down the road for a turbo...).

You may have to grind the water pump. You'll need a longer brake booster hose. And you'll need to clearance your firewall for the MAP or relocate it. I just relocated it and it makes it easier to troubleshoot since you can get to it easy.

Oh and last thing. The FAST is a piece of **** in terms of build quality and fit and finish. Atrocious garbage. Try to figure out a way to get the bolts to stay. With blue loctite they still come loose, and I end up with vacuum leaks through the shell of the top and bottom. Whee!
The billet fuel rail kit in red off ebay is less than that, and looks much better in my opinion.
Old 03-14-2016, 10:44 AM
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I know my car would have made more power with a 102. As others have stated, it wasn't worth it to me. I'll just get the 92 ported at some point. Do what makes you happy.

Who actually designed the fast intakes?


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