ackrepps

Thanks. Love the dragon.

jphughan

I haven't posted on RL in a while, but this topic has pulled me back in. I've read this whole thread as well as the whole 4.25L thread and I'm seeking insight from DeMan GT4 owners and/or Rick himself as to whether the 4.5L would be a good choice based on my goals, or whether some other setup might be a better fit. My GT4 is a dual purpose car. I run 10-12 track days per year (mostly CotA), but still enjoy driving on the street, which is why I have about 25K miles on it at the moment.

Goals

• GAIN lower gearing for 2-5. The Guard gear set sounds perfect on this front (along with the diff I'd likely get.)
• AVOID getting so much power that 1st through 3rd become basically unusable on stock wheels and tires. Extra power and better delivery are desirable. A stereotypical hotrod or something that pretty much requires larger tires and/or slicks to use effectively, not so much.
• KEEP stock exhaust volume and overall sound as much as possible, even if this reduces power
• KEEP ability to register the car in all 50 US states, even if this reduces power

Would a 4.5L build be overkill for my purposes, or even incompatible with them? If so, what would be a better option? Literally my only gripes with the car are gearing, somewhat low power, and somewhat awkward power delivery. Those are also the main reasons I've thought that a GT3 would be in my future, but I happen to like the GT4's looks better than the 991 and 992 GT3, especially the rear. (I finally realized that it's mainly because the wing on the GT3 is mounted so high and far forward on the body, leaving its *** hanging out well behind it, which I realize is the nature of rear engine.) So I'd probably get a Touring if I went that route, but even then I really prefer the size of the GT4 over the GT3. So the prospect of being able to solve gearing, power delivery, and overall power without getting a bigger car or spending as much cash is very tempting. But I'm specifically NOT trying to add so much power that the car becomes a loud, unruly handful.

Any thoughts would be most welcome.

colnagoG60

Why not do a re-gear, and a tune w/high flow cats? The tune will smooth out power, and higher flow cats will at a little more power with the tune, but not increase volume "too much"? You could always do a motor later. I keep going back and forth between "just doing motor, with stock exhaust bits", and "just doing a re-gear", because I just really, really, want to know what stock power and shorter gears is like.

jphughan

Regear on a tuned stock motor (+ a Guard diff) is definitely something I'm considering. The main part that's giving me pause is that there's now a replacement mainshaft to regear 2nd, but apparently it's part of a setup that's specifically designed for the characteristics of the 4.5L motor AND exclusive to DeMan. I haven't found any data as to how well that gearing stack would work with a tuned stock motor -- but I'm curious if anybody has impressions from running that setup. The other concern is sort of the "While you're in there" concept. If I'm already going in there for gears, a diff, and exhaust -- and shipping it from TX to NY -- and later decide I want the engine upgrade, I wonder how much redundant labor I'll be paying for compared to if I'd done it all at once. I suppose I can just ask Rick that. I'm trying to find someone local who actually has a 4.5L setup to give it a try, otherwise I may just have to fly up to NY to try one of Rick's cars. This is a bit more extensive and expensive than I'd want to go for sight unseen, and forum posts and videos will only tell you so much.

sonorous

I think my goals are very aligned with yours and I proceeded forward. I don't have my car back yet so I can't really give a review and reflect on my decision. The GT4 really checks a lot of boxes for me and I knew mine was going to be a keeper. I was not even planning to do any engine mods. But since Rick made this great OEM like product, and I plan to keep it for a long time, I figured it would be really fun to turn it into the GT car it should have been. Once I got to take a ride with Rick in a 4.5 I knew that I would do it eventually but I did still have reservations.

The gears are and obvious choice and will make backroads that much more fun.

As crazy as it might sound, I am concerned about the high power but really only for the track. For the street the power band and power delivery are awesome. My concern is on track, but not about putting the power down, but how much that power might get me in trouble. I only recently started tracking so I have a lot to learn. A stock GT4 is much more of a momentum car than say a GT3RS. Momentum cars teach good driving better than high horsepower cars. I have been a passenger in some very powerful cars on track with pro level drivers and it can be intimidating. I would not want to get myself into a situation over my head. But ultimately, it is up to the maturity and responsibility of the driver, and I am going to trust that I will be able to control myself.

I also had your exhaust concerns and wanted to avoid the stress of emissions inspection. I am going with the stock exhaust with catted headers and x-pipe. As I understand it, this new setup will only be a couple HP down from race headers, keeps the volumes more in check, and is inspection friendly in NY (I think in all 50 states). My only concern with noise is tripping meters at certain tracks but I think with the catted headers this won't be an issue. And if it is, then turn down tips should solve the issue with minimal hassle.

jphughan

Thanks very much for this. Sounds like we're very aligned indeed. Part of my hesitation is the question of whether the GT4 will in fact be a keeper for me. This would likely nudge things in that direction, but I've thought that ALL of my cars were probably going to be long-term keepers, and yet I sold two of them after 4 years each and ended up adding a Golf R alongside the GT4. So basically my car plans have not aligned with car reality thus far at all, which makes me wonder what will happen here. Having some sense of resale impact might help a bit here, but there's not a lot of data on that front. I do see the two cars listed on DeMan's page for $120K as of this writing.

I've also never really been the type for power mods in the past and was always happy to have a "mid-power" car on track -- if I wanted a Z06, I'd have bought one -- but a few months ago I put an APR tune on the Golf R just to spice up the DD a bit more, and somehow that's now caused me to slip all the way down the slope to contemplating this! You'll very likely be able to relate to that feeling if you've just started tracking. It's a ton of fun, just don't taint it by adding up the receipts.

Please do report back as to what the car sounds like with your exhaust setup, because that sounds like exactly what I would want to do. If it's a stock or near-stock experience in that respect, then I'll probably fly out to DeMan to try a 4.5L, knowing full well that I'll be a goner once I do.

jphughan

One minor follow-up: How significant is the change on track in terms of fuel consumption? The reason I ask is that at CotA with the extended range fuel tank, I typically go through 1/3 of a tank per session, which means I can go two sessions before having to fill up. Is that likely to still be possible with a 4.5L setup?

oakmont

That is a good question. I plan to find out this coming weekend at COTA and will report back 😉

Martin Anders

It might be possible that just getting a regear (e.g. a 10% shorter final drive from Holinger) + headers/plenum/throttle body and a tune = 10-15k USD will get you what you need, is fully reversible in case of you selling the car later. will get you 430-440hp + 10% shorter gearing will feel like 450+ hp car (997.2 gt3 will be less fast)

jphughan

Thanks for the thoughts. I have actually considered a regear plus a Guard diff. I'm admittedly not a huge power junkie, and I had some realizations at CotA this weekend. While instructing my student in a 991 Turbo S, I realized that straight-line performance doesn't do all that much for me. And while running my own GT4 with its stock power and tires, I realized that apart from the long straights, there aren't too many places where I can be full throttle for a meaningful period of time or where I could carry more speed through corners if I could reach a higher speed before the turn-in point. T10 is a notable exception to the latter, but apart from that there are already some corners where I have to ease off the throttle a bit before the corner. Those realizations basically told me that adding a bunch of extra power might not be the right path for me.

So back to the regear and diff. The regear is tempting mostly because I'd be able to shift more on the road, which I really enjoy since the GT4's shifter is so great. I'd still be reluctant to change the final drive since I'd like to keep 1st and 6th as they are. The Guard gear set that DeMan recently introduced for the 4.5L sounds great, but it's also advertised as being specifically designed for the 4.5L's characteristics, so I'm not sure how well it would pair with a stock motor or if it's even available for purchase separately from the 4.5L conversion. And then I have to wonder if it's worth sending my car to NY just for a regear, since Guard has some approved installers for their diffs here -- but the Guard gear set for the GT4 is apparently exclusive to DeMan. Lots to think about....

burnergt4

Maybe you could have your shop send just the trans to NY for the regearing?

awrryan

the sharkwerks Gt4 has a 3.8 and is regeared and apparently drive tribe loves it. Watch the YouTube video. It’s great.

Montaver

The Sharkwerks implementation isn't a good solution because it doesn't change 2nd gear. The long 2nd gear is what really prevents you revving it out on the street.

The Deman gearing will be great regardless of stroker or not, as it shortens the 2-5 gears. You can definitely buy just the gearing if you want, I have spoken to Rick about it.

awrryan

Thanks for pointing that out!

Luca Paindelli

Our GT4 is going back to Rick tomorrow to complete the work: last August we dropped it off to have the engine done, but at the time we opted to keep the transmission stock. After driving it around like that for about 1K miles it became clear that although fabulous, it was still missing something: having driven his test mule with the full package, the 4.5L and the transmission work so well together. Acceleration is even better, but it's also and primarily how you go through the gears that is so rewarding. For whatever my opinion is worth, the package of engine and transmission are a match made in Heaven.

The change will include obviously the regearing of 2nd through 5th, a new LSD that Rick developed and has exclusively manufactured for him, and the FabSpeed xPipe tips (stock PSE with just the xPipe tips) which after testing out a multitude of different exhaust combinations on the dyno turns out to be the only the thing that the car needs to get maximum power out of a 4.5L...

Then I'm done... Well, that is until the next thing on the list, but that's a story for another day...​​