The Last Indian

[Robert]

Building a splitter that actually works as a splitter, is an enhancement to the NACA duct Ram air function! Plus enhance the overall front end look! This final design developed over about a 8 month period.
First of all I wanted a splitter that would add to the look of the front end! What does that mean? Well some, or all may not agree with me, but while I love the throwback to the muscle car coke bottle shape of the 7th Gen GP. I have always felt that the front nose, especially from the side view looks weak! Why? Well, my opinion is the front nose from the side comes to a point just above the license plate cover. This is enhanced by stock hood which has a forward slope , than a sharper angle of the cover at the grille area. A short flat area at the license plate cover & than a step back angle below that. This makes a noticeable progressively smaller, top to bottom appearance as you move away from the windshield to the front nose.
I wanted to beef up the look of the front nose, I.E. make the nose look less slopped & more blunt as opposed to pointed. While removing as much as possible the slopped look of the hood towards the nose design.

So that first step was the F.1 MPD hood. Because this hood visually tends to raise the front profile of the hood. Than the SD air dam. This piece pushes the lower portion of the front cover out forward, giving the side profile a more blunt look, as well as beefier one. Still I wanted a little more blunt appearance & less roll at the very bottom of the cover. So the splitter needed to be that piece! Plus perform as a splitter & enhance the NACA duct! Notice that the first picture is with the stock front cover & the first splitter I made. The next two are with the add of the SD air dam & the second splitter I made, which was modified to become the final splitter used. Notice in the 4th picture there is an overall appearance of a more blunt front end.

Hopefully these pictures will detail that objective.

That turned out great! I've seen a few splitters on these cars, but nothing as clean as that. It really transforms the front profile. I've been thinking about doing something similar on my '90 and '93 GPs.

 

[RebelRacer99]

Looks good, I like what you did with the headlights too.

 

[Last Indian]

Looks good, I like what you did with the headlights too.

Yes, that scheme on the headlights effectively changes the appearance of the front. It tends to beef up the front by removing the visual of elongation, I.E. thinning, because of the long effect of the stock headlights to the front.

 

[Last Indian]

Splitter build. The schematic of the air foil shows the effect the outboard upturned wings have on the air movement over them & why they help supply air to the NACA duct inlet.

 

[Last Indian]

Another body change/upgrade was the widening of the rear cover. As you will see in the suspension post there is a substantial increase in the track width, both front & rear! I have seen other seventh generation GP’s with a wider stance & the thing that has always struck me is how weak it makes the car look from the rear! For me, a car to look intimidating from the rear it needs a wide stance, with wider tires! These wider tires need to be retained within the body though! Not by much, but all of the body! Yet because of the GP’s design, the tires at max width, I.E., just inside the fender wells & even the rocker panels, basically right at the edge. The back cover will sit noticeably inboard of the tires! This, to me makes a weak look; especially from the rear view!

So once again I wanted to change this look! So I needed to modify the rear cover to encapsulate the tires within the body, but just within it. Yet I didn’t want a noticeable shift in the design! Just a subtle one. The results, at least for me was just right.

This change also required a modification to the inner fenders!

 

[Last Indian]

More details on how to proceed with the back cover!

 

[Robert]

Now that looks a hell of a lot better, Did you use plastic weld/epoxy for this?

 

[Last Indian]

Now that looks a hell of a lot better, Did you use plastic weld/epoxy for this?

I’ll try to explain this process a little better. Once you split the back cover as I did, following the groove that is molded into the cover, to separate the back valance, per say, from the rest of the cover. You’ll need .025 thick aluminum. Make a plate that can be used to connect the two split pieces of the cover back together using pop rivets, as I show in the one picture. When doing this part you need to have the cover on the car so you can see how much to pull the valance part of the cover back to create the gap I show. This also shows you where the edge of the cover is pushed out to with relationship to the wheel well / tire. I would suggest some clamps will help with this process. Then using more of the .025 aluminum make a insert plate to fill the gap of the cover. This plate should have a folded edge upset to add strength to it. Then I used 3M panel adhesive 38315 to bond that plate to the cover. After that I used only USC icing filler to finish the cover.
All of this said, before you affix any of it permanently you need to modify the inner plastic fenders! These have a huge impact on giving formality & strength to the whole configuration. I will follow up shortly with that information & detail.

 

[Last Indian]

You might want to get a second set of rear inside fender wheel well covers to modify. Either way I would suggest cutting the back cover as above off the car. Then install it completely with the inner fenders in place, but not attached to the cover. Once installed you going to start to pull the fender well part of the cover over to where you want it to fall relative to where you want it on the tire. Once you’ve established its position you’ll need to take some clamps & the aluminum plate, clamp the two separated parts of the cover together. This should make the cover more ridged & create the gap you see between the valance section of the cover & the main cover. Do both sides in this manner to gain uniformity. Now you are going to see a large gap at the wheel well between the cover & the inner fender. You now need a piece of cardboard or construction paper. You will make a template that overlaps on the inner fender & butts up to the inside edge profile of the cover. Just as the original inner well covers originally did. See pictures! The rest of the pictures are fairly self explanatory, but if there are questions please ask.

 

[Last Indian]

One thing I did not touch on, so I will do it here is this. Both front & rear covers are fairly free floating, I.E. not rigidly mounted! As they, Car manufacturers, love push clips. Which real only keep panels from coming apart, but real does nothing to actually secure parts together or affixed to the actual car body structure. So again for those who have an interest, these are the things I did to change that. The results were front & rear covers that performed more in the manner of the old school cars! Once complete they were solid, I.E. did not move. This included headlights, 5mph impact foam that is mounted to the impact bar among others things.

So first up are the headlight brackets. These are actually poorly done. The bracket is fairly long & only attached at each end by spot welds. Leaving a long section of a steel bracket to just vibrate. So I machined nylon spacers to go in between the bracket at about mid point, side to side, both top & bottom. Drilled a hole through the bracket & core support for a 8-32 machine screw. Than opened the hole in the bracket up for clearance. This allowed for a ridged bracket! No more vibration!

Additionally note the affixed pads that are mounted on the impact bar! These are a three stage pad. The first layer is a anti vibration pad & is bonded to the impact bar, than a urethane foam kneeling pad material bonded to the anti vibration pad. Than the top layer is a ¼” neoprene sheet material bonded to that. These all stack up to sit under the headlight housing. When done properly the headlight housings rest slightly on the assembly of pads. The headlights are now fairly ridged! This is extremely important if you are running HID projection lights, as vibration becomes very noticeable when using these lights.

(As A Side Note)

If you are running HID projection headlights you are also running a regular open high beam. Unfortunately this open high beam on its own is pretty in affective. Also unfortunately these cars, unlike their predecessor don’t use all 4 headlights on high, but turn off the projector lights! I changed this! I rewired the high beams so all 4 lights are on when on high beams. This action makes a huge difference on a dark road at night.

 

[ThatSlow.W204]

I keep saying this but the attention to detail is top notch on this build, absolutely awesome! always wanted a highly detailed build like this, I forgot to ask, maybe you’ve already said it and I missed it, did you ever get to measure the weight distribution after all the stuff you got to do? It’d be very cool to see the difference!

 

[Last Indian]

I keep saying this but the attention to detail is top notch on this build, absolutely awesome! always wanted a highly detailed build like this, I forgot to ask, maybe you’ve already said it and I missed it, did you ever get to measure the weight distribution after all the stuff you got to do? It’d be very cool to see the difference!

So to answer your question, yes I did all that upfront work in the very beginning knowing what I wanted to accomplish. I sat down laid out the suspension geometry as it was, then looked at what I could effectively change. Than calculated the numbers & began to make those changes. Now this did take place in incremental steps. In the end the goal was to lower the CG, raise the RC, increase the track width & increase the SSF number. Eliminate torque steer, decrease braking distance, increase power & increase cornering speed as well as stability. The changes were notable in the end.
I needed to look at factory perimeters, (SSF) static stability factor (1.37), weight distribution(65/35), CG(22.45”), front RC(23.70”), rear RC(23.70”) wheel base(110.5), track width ft.(61.7) rr.(61.1) & suspension geometry. These numbers are not very good for a car that you want to handle, they're pretty normal for FWD though.
After modifications, (SSF)(1.76), this is a sports car number, weight distribution (54/46), CG(20.85”), front RC(25.88”), rear RC (25.88”) wheelbase 110.5 (same as OEM), track width ft.(73.5”), rr.(73.25”) & suspension geometry completely modified.
So without getting to technical & lengthy, it goes like this. To effectively increase handling you must lower the CG & raise RC & weight distribution if that applies needs to be 50/50 or as close as possible. So the first thing you would always prefer is to lighten the car where needed, but when you can’t you move the weight around and where necessary you add some, thus was the case here. Than you look to increase the track widths & last modify the suspension components to take advantage of those changes.

I know lots of folks lower their cars & that certainly is their choice, but I don’t believe they really understand what that does to the RC! And while it lowers the weight over the wheels; it virtually has no impact on CG! But! & it’s a big one it, changes the the RC in a bad way!

 

[ThatSlow.W204]

So to answer your question, yes I did all that upfront work in the very beginning knowing what I wanted to accomplish. I sat down laid out the suspension geometry as it was, then looked at what I could effectively change. Than calculated the numbers & began to make those changes. Now this did take place in incremental steps. In the end the goal was to lower the CG, raise the RC, increase the track width & increase the SSF number. Eliminate torque steer, decrease braking distance, increase power & increase cornering speed as well as stability. The changes were notable in the end.
I needed to look at factory perimeters, (SSF) static stability factor (1.37), weight distribution(65/35), CG(22.45”), front RC(23.70”), rear RC(23.70”) wheel base(110.5), track width ft.(61.7) rr.(61.1) & suspension geometry. These numbers are not very good for a car that you want to handle, they're pretty normal for FWD though.
After modifications, (SSF)(1.76), this is a sports car number, weight distribution (54/46), CG(20.85”), front RC(25.88”), rear RC (25.88”) wheelbase 110.5 (same as OEM), track width ft.(73.5”), rr.(73.25”) & suspension geometry completely modified.
So without getting to technical & lengthy, it goes like this. To effectively increase handling you must lower the CG & raise RC & weight distribution if that applies needs to be 50/50 or as close as possible. So the first thing you would always prefer is to lighten the car where needed, but when you can’t you move the weight around and where necessary you add some, thus was the case here. Than you look to increase the track widths & last modify the suspension components to take advantage of those changes.

I know lots of folks lower their cars & that certainly is their choice, but I don’t believe they really understand what that does to the RC! And while it lowers the weight over the wheels; it virtually has no impact on CG! But! & it’s a big one it, changes the the RC in a bad way!

I’m so happy somebody else here knows a lot about the suspension stuff, I’m not as detailed as you with that stuff but I do know quite a bit from growing up at the shop and constantly helping my family with the racing stuff, I have learned a lot over the years and I’ll continue to learn more, the learning will never end. handling has always been my go to thing before speed, I will always love a car that turns better than a car that can only go fast in a straight line, I forgot to mention to you but your part of the reason I started ordering wbody parts agin, decided I’ll do one last full out special (to me) build before I go, unless of course we get these forums big, then I’ll be stuck haha, but I always mention to many people the factory weight distribution on these cars is pretty bad, it’s alright for a fwd car as you mentioned, but for performance driving it’s for sure not good at all and 1000% can be improved, as you have proven. When I did the LFX swap on my 03 Monte I did a lot of things to get weight off the front, ac delete, the engine weighed less, got rid of some other stuff up there that wasn’t necessary, and man, that thing was completely different. this time around I’ll be doing the same thing, but even more in depth, battery relocation, ac delete, etc, by the time it’s done it’s definitely going to stick, that’s for sure. Sorry if this is hard to read, I’m pretty tired Lol. But hey, you talked me back into a w body for now, but after this I’m pretty sure it’s my time to go to better platforms again. ALTHOUGH, this time I’m not going to make the mistake of doing all this to a rusty car, because this time I’m going to keep that build for a very very very long time.