I know people say Walbro 255 all the time but I'm not sure there really is a '255'.

The Walbro GSS340 pump delivers about 63 gallon/hr of fuel at 13.5V and 60 psi. Not 100% sure but I think that is the pump used in the Racetronix kit.

The Walbro GSS242 pump delivers about 43 gallon/hr of fuel at 13.5V and 60 psi.

 

Interesting. I have been looking at the racetronix kit with a hotwire because I am not sure the 255 will support my needs. What do you run Qwik?

 

I have a 4th gen plastic fuel tank with the Racetronix kit. Essentially a GSS340 pump. A Racetronix pump with 3/8 fuel line will support 600 HP naturally aspirated all day long. Some people even get away with 600 RWHP but results will vary.

You can call Racetronix and talk it through with the owner. Smart guy but has really poor listening skills and can be difficult to talk to.

I think you'll have a much better time talking with Nate at Nasty Performance.

 

Thanks for the insight. I will be running a 4th gen tank as well and have been looking at this kit. What regulator are you running and does this kit use a hotwire?

 

I have stock in-tank fuel regulator. Some people will gasp in horror.

Yes, it came with the Hot Wire kit but the wire harness is made to be plug-n'-play into a 4th gen car. Overly complex with extra wire runs and connectors we don't care about. I broke it down to simplify and by the time I was done I just ended up using the 10 AWG red wire and ground.

If you look at post #1 of my build thread you will find an index to [possibly] useful links. There is a topic heading for fuel system. If nothing else you'll see how the Racetronix harness is put together so you can hatch a plan what you want to do.

 

Yes have had no trouble with it using the LS3 crate we have in this swap... Fuel pressure and injector flow duty cycle have been great

In other swaps i have also used the 4th gen plastic tank and the racetronix kit... currently the camaro i am presently working on with my Ramjet 350 project is using this.

I like the 4th gen tank and set up, you can see how i did it on my latest swap here in post 15
https://www.thirdgen.org/forums/engi...ort-coupe.html

One thing i am not completely sold on is the small venturi feed used in this set-up... i am thinking about doing something different with the 4th gen set-up in my next swap but i need to think about it some more.

The racetronix pump i installed in my first LS3 swap back in 2008-2009 winter is still working well. However probably only about ~5000 miles on that 85 iroc LS swap

 

Thanks! That will be a big help for me. I think I will need to sell my DSE weight jacks for the UMI units. At first pass they don't seem compatible with the UMI spring perch.

 

yes i like the UMI weight jacks so far much better than the DSE (i do have the DSE ones installed in my 85 IROC with the UMI spring perches but i needed to do some mods to make them fit... see posts starting at #392 in below thread

https://www.thirdgen.org/forums/ltx-...ne-swap-8.html

to be fair i haven't driven on the UMI ones yet, but they fit and engage much better and expect they will perform great

 

Does it dump using a drain **** on the bottom, or does the bottom section unscrew from the top?
Would you use it again or try a different brand?

 

the bottom unscrews, see some additional pics

so far I like it a lot and better than the one that I have in my 85 iroc ls swap that uses a drain ****... the drain **** can be hard to access and messy (I have a tube on it to make it less so, but still more hassle than this one)

 

Are you using the stock gauges? If so what needs to be done to get the speedo, tach, oil pressure and coolant temp working? Thanks!!

 

Yes using stock gauges.

For speedo and tach, they are driven directly from outputs from the LS E38 ECM in the Speartech harness (their harness includes the correct pull up resistor for the tach) with appropriate tuning in the ECM for correct speedo 4000ppm and tach drives

For coolant temp instead a 3 pin '98 camaro coolant temp sensor in the drivers head. this supplies signal to both the ECM and cluster gauge independantly. GM 12551708

For oil pressure use a single pin sensor from '02 camaro to drive the cluster. GM 19244505

 

 

i had used the DynaTech on other swaps so i knew that i could get them to fit well and were a high flow cat so decided to just stay with what i knew would work. i am sure others might work well, it was just a pick based on previous good experience

 

 

Hawks sells a bracket mount for the GM DBW pedal.

 

 

 

Back in the day the 255 was 255liters per hr according to the fox mustang catalogs. There were a few different LPH sizes, maybe still are.

 

Nope, it's designed specifically for 3rd gens with the GM DBW pedal.

 

note that while I like Bruce's items a lot generally, I did not like this pedal mount. It fit well, mounted easily, but in my opinion it pushes the pedal way too far forward. Both my son and I both felt this way and found it awkward

we ended up making our own mounting plate arrangement that puts the pedal in a much more standard position. it works very well... I will try and take a couple of pics

 

here are a couple quick pics of my pedal mount, hard to see but hopefully you get the idea. Made a standoff that mounts to the original pedal studs and then put the plate on. I have plans to also put a mount at the original throttle cable exit but didn't get to it yet. It is stiff with even just the original pedal studs

 

just a note on the hawks dbw pedal mount; it is designed for car pedals only. if you're using a truck dbw pedal assembly, it will not work. I ran into this on my build, had to cut up the truck pedal and mount it similar to alan's post above.

 

Any idea how much the engine moves forward and down? Does the pan hang lower than the k-member? I'm looking at going down the same road as you have with this build.

I already have a F body pan and was curious if this would still fit with the UMI/Holley combination, moving forward would help me with down pipe clearance

 

How do you like the Speartech harness overall? I'm trying to figure out who's to use, which model or whether I should attempt my own. Mine will be going on an LQ9 6.0 truck engine. I see Hawks can provide a true PNP but that is some hefty money for that harness and I'm getting married in a couple of months.......

Also, what engine accessories did you use and how did you attach? Maybe I missed that post.

 

I gotta say looking at the pictures of your swap, it looks like you and your son are doing an awesome job! I'm also quite jealous of your shop and equipment you have. LOL. Car looks great! I'm seriously considering doing a auto to T-56 swap in my '87 Formula. I've got a Gen 1 383 with the long tube headers so that creates a bit of an issue with the bellhousing. It looks like it can be done with a quick time bellhousing and I'm looking at going with the all new trans and additional parts as well. I'm assuming you would say the T-56 swap it totally worth the trouble and cost. Keep up the good work!

 

sorry for the slow replies, here are some thoughts-

when I had talked to UMI about the relative position of their k-member, their claim was the base k member as utilized with a SBC positioned the engine in the same location as the factory k member. I would say this seems likely to be a reasonable statement as I have used this k member as well on SBC projects and it seems relatively in the same position as factory. of course with the LS you know also have the perch mounts that you add. I built my own as shown above and the adjustment range allowed me to fit it to the position I desired. as far as f body pan vs holley, I know if you do a quick google there is a print that shows the relative dimensions of each vs each other


yes speartech harness is a good harness. I made some changes to it as I wanted the FPR on the driver firewall, etc, but overall it is very good. the accessories we used were the GM LS vette set-up

Yes I really like the t-56. note that the LT1 type t-56 typically used on sbc applications uses a pull type clutch that is a little different in feel, at least to me. still works good, but I notice it is a different feel compared to the ls t-56. on both when speed shifting watch quick shifting from 3rd to 4th... ie money shift (hitting 2nd vs 4th!)

 

Here are oil pan dimensions, Post #936, https://www.thirdgen.org/forums/ltx-...ml#post6193942

 

one of the things that my son and I have never liked about the swap has been the performance of the pbr LT1 rear brakes... these came as part of the hawks 8.8 that we swapped in originally when still a SBC... brake pedal has not been great and rear brakes seemed like they were doing very little

anyways on my 85 IROC LS3 swap (see separate thread) i had recently upgraded my 9" moser from the original BAER pbr LT1 rear kit to wilwoods and it was a huge improvement all the way around. last winter i did the same on my son's 87 Formula and what a difference... since this set up was different and had some unique aspects i figured i would share some information

The thing that makes adapting the Wilwood brakes to this 8.8 rear is that since it was originally set up for LT1 brakes, the rear had some very GM specific features, ie
- Moser 7900 FM ends... ie Chevy end pattern bolt arrangement with Ford Big Bearing in a flush mount configuration (~0.8125 depth for bearing)

Here is a list of basic information / parts that my son's Formula has after this swap

- 4th Gen Pedal Set
- 4th Gen Brake Booster
- 4th Gen LS Brake Master Cylinder
- Wilwood Adjustable Proportioning Valve 260-15048
- 4th Gen LS1 Front Brakes (bigbrakeupgrade.com kit)
- Wilwood Rear Brake Kit Wil-140-7578 DR as a base plus Wilwood 120-9703-SI calipers instead of those supplied with kit

 

some pics of the rear brake set-up with the Wilwoods

 

The Wilwood Kit 140-7578 DR was the closest kit I could find to accomplish the swap. It features
- 12 Bolt Chevy End Pattern with 2.81" offset
- 12.19" Diameter Rotors / 0.81" thick
- Dual Piston 1.38" calipers for a total piston area of 3.00" ^2
- Integral Parking Brake

I ended up also buying Wilwood 120-9703-SI calipers as i wanted a caliper more like what I had on my 85 IROC LS3 swap. This caliper has the same piston area as the one that came in the kit, but it has other features making it more capable on pad retention, bridge stiffness, etc ... This wasn't really necessary but is what I wanted and in the special chevy pattern kit Wilwood doesn't offer a lot of kit options, maybe if i would have called they would have made a special kit up for me with this to start

This now got me close to something useable, but a special shim was required to be made as i will illustrate below

 

From now on any other rear ends I get will always be with Ford Big Bearing ends with the Ford New Style Torino ends with 2.50" offset... this makes getting brakes easy as Wilwood and others have a lot of offerings for this standard end pattern.

The Chevy Flush Mount moser ends are nice in that you can use the big bearing but unless you are going to run PBR LT1 brakes end up being quite a headache, at least that is how it was for me.

Wanting to go to the WIlwood rear brakes for better brake pedal and performance with a kit that still has a good integral parking brake lead me to the 140-7878 DR kit that as a baseline got to the right end bolt pattern and close on the offset. However the Wilwood brake bracket sits on the flush mount but lets the bearing pass through so you now have a space between the end of the axle end and the bearing retainer that will now sit on top of the Wilwood brake bracket.

I thought about a lot of different ways of dealing with this, but in the end decided the best thing to do was stick with the axles with the Ford Big Bearing ball style that stayed flush with the original axle end and used the separate internal seal and then make a shim to take up the thickness of the Wilwood brake bracket on the outer end

The Wilwood Backing Plate is ~0.26" thick so needed a shim to take up that distance and also be able to have a cut-out allowing it to slip over the axle diameter for the install

For base material I used a 6061 Aluminum Tube that was 3 1/2" OD and 2 1/2" ID that I sourced from McMaster Carr. My friend rich then machined for me out of this two shims that ended up ~0.259" thick with a 3.150" OD and 2 1/2" ID (no change to stock tube) with a 1.93" opening

 

Some additional pics

 

With this set up I was able to then get the caliper shimmed correctly and well centered on the rotor. I ended up shimming both on the caliper side and also between the mount and the wilwood base bracket

For shims between the bracket on the plate I used 8mm ARP washers. For the shims between the caliper and bracket I used the supplied Wilwood kit shims

 

For the set-up of the parking brake cables refer to the pics and info that are in my 85 IROC LS3 Swap thread

https://www.thirdgen.org/forums/ltx-...ml#post6489742

 

After bleeding I did then out of curiosity put a brake pressure gauge on the front and rear

With the Wilwood proportioning value backed off two full turns from max I was getting ~1200 PSI on the front caliper and ~975 PSI on the rear caliper and a great pedal (i was using a vacuum pump to the booster for this testing

Once driver season emerged last year, real world results confirm great braking. In fact I need to turn down the proportioning valve further by a couple of turns to get straight hard braking stops as the rear brakes are so capable. Pedal feel is great

 

what headers did you end up? did you ever try the umi k-member combination with the holley swap headers? not sure if they even still make them.

 

Although the headers aren't made anymore they do in fact work with the UMI K-Member. They should work with any aftermarket unit since they were designed around the stock hulky k-member.

 

damn, they cut them, that sucks. any other good fitting nice quality ones?

 

They were cut due to some new EPA rules, there is a locked thread around here with folks gripes. Kooks makes a set (I think they still do) and speed engineering makes a set. Chinese versions on ebay too.

 

I'll have to look that up, sucks to hear, I had them in a previous car, really nice quality and build.

 

Yes, this is going to put a damper on high power naturally aspirated builds. I think people will end up doing a lot more turbo builds instead because the exhaust manifolds are still available (not specific to any vehicle chassis). My used exhaust is going to be worth more than my car in a few years.

 

You selling an exhaust?

 

No, sorry, I was just making a joke that my exhaust will become worth more than my car.

 

The Brakes look great!



But shouldn't there be Floating Rotors used with those Brake Calipers...

 

wilwood has all sorts of kits, the kit i got was specifically for this type of set-up and i upgraded to a better caliper, but same lug type mounting 4 piston topology

base kit - https://www.wilwood.com/BrakeKits/Br...no=140-7578-DR


they work great... from now on i am always going to set-up my swap axles with ford specs and use wilwood brakes, so much better than the LT1 type ... have this now on two of my thirdgens

 

While my son has been away at his duty station over the last year in the navy , I had his Formula repainted. Came out awesome! Hope he likes it when he is back on leave in a couple weeks

 

Beautiful Formula, I'm sure he'll be proud.

 

Couple more pics

 

Very beautiful Formula, I'm sure he'll be proud on work you done.