gt35/40 What's the big deal?
 

Everyone seems captivated by the GT35/40 yet it's numbers don't seem overly impressive or groundbreaking. Why the sudden 35/40 craze? No flame intended.

respectfully, -Rob

I'm stayin out of this ;)

then your best bet is NOT to get a GT35/40 ..... you could be like everyone else a get a big turbo like a T78, T51R and wonder why you get smoked by a twin turbo or "small single turbo" car

as ive seem numerous times on this forum.. there seems to be more people with "big turbos" on there cars and they cant get over 400rwhp and complain there car is not fun to drive anymore.. .. theres a couple of owners here with a big turbo set-ups that run well but the ratio is overwhelming

this is talking out of experience as ive had the T78 (twice) HKS T51Rkai, Apexi RX-6, GT35/40, HKS T04R and i have to say since i drive/enjoy my car 99% on the street the smaller single turbos were definately better and funner for me.

theres many alternatives out there and you need to get the turbo thats right for YOU... some people here will tell you X turbo is better than Y turbo but they dont even have a single turbo set-up themselves (or one that even runs)!

do a search and you will see the guys who actually have experience with certain turbos


good luck,
Steve

steve... please post what you thought about each of those setups and compair them... i am looking for something that i can daily drive and have fun but still have a good time at the strip and run some good times...
-Keith

Keith,
If your lookiing for good for the street and FUN to drive, look at "smaller turbo" set-ups...here are some examples:
1. HKS T04E
2. APEXi RX-6
3. Greddy TD0620G
4. XS Eng T04E
5. A-Spec GT35/40

these are great turbo set-ups for your needs.. these set-ups are considered streetable by the manufactuers... these same manufactuers dont suggest running there "race" set-ups for the street i.e. Greddy T78,T88, HKS T-51Rkai. etc.. if you plan on running one of these "race" set-ups a good tuner is essential as most of them require extensive EMS/Fuel upgrades to get the most out of them.

good luck
Steve

thank you so much for the speedy reply!!! but i think i should have asked the question differently... what would be a kit that would make good power for 1/4 mile and still not be a dog on the street??? and i realize that i will need supporting systems... i already am running a microtech and have a built motor and tranny so i am somewhat getting there... lol
-Keith

ok, what times would you consider good for the 1/4 mi? remember our cars weigh 2800lbs (FD as an example) 375-425 rwhp will get you mid to low 11's if you know how to drive your car correctly down the 1/4mi .... 60ft is everything..using that as an example the Apexi RX-6 or GT35/40 will get you there

but remember even if you put any of these kits on your car i highly suggest you finding someone with experience with your EMS/Fuel set-up to get you where you need

Interesting reply, seeing as how you have no idea what my goals are nor do you know anything about my car. I hope you didn't take offense to this objective question. I only ask this because the turbo seems very moderate both in power capability and spool up. Maybe that is why everyone loves it. It's a nice middleground between t3/t4 and T-88.

At what RPM are you 35/40 user reaching full boost?

What type of power are you making to the wheels?

Steve no longer has a GT3540.

I dyno'd mine 378 at 6900RPM. Boost was ~14-15PSI. I told the operator to rev it to 8300 but he didn't. The A/F was heading slightly lean wobbling between 12.5 & 12 so I guess I can't complain. Torque was 288, & when compared to the "405" HP plot posted in this section it looks like I'd have hit a good 420RWHP if the test was taken to the appropriate RPM. I will dyno again once the fuel system is done, & eventually I'll install H2o injection & try out some high boost.

Anyhow I'm pleased, & the car is still pretty much just thrown together. Very little tuning has been done, & I still haven't received my EGT gauge...

Just my experience.
Eric.

what are your thoughts on the T62-1 turbo? Sorry to pirate your thread.

My HKS T51R KAI is everything but boring on the street. Fast spool, great power and sounds sick. I dominate all twin/single cars in my area from a stop. No lag here.

I heard Nocab72 say he is getting like 20psi @ 3700rpm or something. Resource what RPM does your T51R KAI hit 15PSI? What would you prefer the T51R KAI or BSC Holset HX35 600HP kit.

resource: what kind of fuel mods are you running? I am about to go single. these twins are getting on my nerves. Just trying to find the best setup ---what exactly is your setup?

I prefer the HKS turbo. I'm running two 1300cc injectors and 2 950cc injectors for now.

My motor is stock ports and probably going to be that way for a little while, I think its down to the KKK/HX35 and the T51R KAI for what I want to put in my car. Or building a custom kit with a Turbonetics or Innovative Turbo.

here's a post by nocab in the "turbo spool needs to be quicker" thread. its a few threads down if you want to read it. here's what he said:
trade me, mine spools too fast for the size of port I have on my motor... full boost (20psi) at 3700rpm, motor don't make no power till 4500 - 5000k. not sure if I have a good or bad problem yet... lol
k

so he has about 478 rwhp(i think) by 3700rpm. not to shabby of a kit in my eyes. thats why mines on the way to my shop:)

Eh.. I don't think so.. there is no way he has 478 RWHP @ 3700rpm. Just because he is making 20psi there doesn't mean he is making the same power as he is @ 8000rpm. I have the 'puny' little HKS TO4E kit and my car behaves similar, very fast spool but you don't feel the rush in your seat until 4000.

resource, what do you consider "fast spool" and great power? Your setup sounds pretty sick. Congrats.

-Rob

How does a Turbonetics T66 compare to all of these others in size, spool time, max power, etc.? I haven't seen too many single turbo cars, so I'm not sure how to compare. I know my T66 is bigger than my friends T3/4 and definitely smaller than the GReddy T78. Other than that, how does it add up?

I'm no turbo expert, but the bigger turbos are moving a greater volume of air at a given boost, so more air, less heat, more power.............Right? I have learned to drive my 97 Supra within its powerband(4000-6700 rpm) It walks away from most any car. In a rotary you have another 1000 rpm(at least) to play with, that's plenty for me. As for 478rwhp at 3700 rpm, you can do that with a T66, and a 75 shot in a Supra, but NO WAY is he making that power at that RPM. In fact I'd say no way to 300rwhp at 3700 rpm..................PROVE ME WRONG :D respectfully submitted C Byck(the doubter)

BTW I did not start this one, but I did lie when I said I'd stay out of it ;)

Piano, how do you like your turbo? what AR/trim?

I thought that nocab dynoed at under 400 at the wheels............ I think Jason made a post about that.

Pianoprodigy I PM'd you

Somebody should PM him (Nocab) and get the straight info.

I get 15 psi @ 4300 rpms. The power that my turbo gives out isn't gradual like a smaller gt35/40 or t04 turbo. It's either BOOM on or off. When it starts to boost, whatch out because it's going to instantly peg the boost gauge.

Sounds like a good all-around setup. Quick spool and plenty of pull. Well done.

okay, i need to apologize for being an idiot on my post, thinking to many things at once with no sleep. nocabs spool is great, not 478 at 3700rpm, (what the hell am i on?) obviously that's his peak. i hate it when i do that. anyway, i'll proof-read my posts from now on so i dont sound like a moron, even though i am:)

oh, and sorry to kyle most of all. for saying stuff about his car that doesn't make any sense.
i guess everyone has an idiot post at least once, sorry all.

I want to know what kind of power Nocab72 can run on pump gas. I doubt he is running 20PSI on pump gas. Whats the power at 15PSI? T51R KAI is going to make that power at 15PSI, however the lag sounds a lot worse. The GT35/40 is already at 20PSI when the T51 is just getting started!

Paximus, I've said way dumber things than that ;)

Forget psi......consentrate on power.

Its hard to compare power when all we have is a bunch of numbers and I can't just go drive all the different single turbo cars. I think I am just going to get the friggin T51R KAI since the RX-7 isn't driven all that much anyways.

Don't sweat it paximus.

Icemaster, I'm assuming that you were considering a GT35/40 before. What has made you change your mind to go T51? Is the 35/40's luster beginning to wear off?

nocabs 20psi is on race gas, 15 on pump, i think he made 430@15psi. i had his dyno's somewhere but now i cant find them. there is also the dyno comparison site, (catnet.com or something), both of them are on there too. if anyone cares to look at them.

Thanks for the follow up Pax.

Maybe someone will find a dyno sheet for his 35/40 FD and post it. Maybe we can also find a dyno slip for a T51 FD and see how they compare at similar boost levels.

Nocab made 416 rwhp @16psi with a tuned raceported motor. Here is the link https://www.rx7club.com/forum/showth...b&pagenumber=3

I just got my GT35/40 kit recently and can't wait to freakin install it.....Will be a couple of months before it's installed though...until then I will continue to boost the crap out of my twins.

note: This post is meant to follow the thread and has no vauable input what so ever.

IMO T-78's & above (that includes the T51) come on like a switch! It's cool if you've got nice tires & are on a dry road, but it can surprise you on a damp road just trying to pass someone on the interstate. Not a linear boost pattern, & definitely not my idea of a street setup/daily driver. This happend to a very nice black FD here in Fl. sweet car that wasn't even that fast. Only about 390 at the wheels & the owner got sideways passing someone on a damp interstate. Totaled FD!

On the other hand, the T-78's & above will make more power! it's a simple concept. Bigger turbo supports higher boost, & greater power. If low drag times, & >20PSI boost levels are what you're after one of these turbos will be the turbo for you!

The GT3540 comes on very linearly. It's very streetable, no surprises, & has a very nice top end. It's been proven to produce over 400 Wheel Hp at acceptable boost levels/pump gas, & will support ~20PSI.

My $.02. Whatever you choose I'm sure you will have a blast!

I've been thinking about the 35/40 as well. I just wasn't sure what kind of power they were capable of. I guess I know now. The other thing I'm wondering is what kind of porting are you going to need to get it to spool that fast. And when you say nocab has a "raceported" motor, is that a bridgeport, huge streetport, P port or what? I was thinking of a partial bridge or full out bridgeport. With that I'm wanting to full spool by 3750 to 4000 rpm. For the guys that have the experience, is that possible? Thanks in advance.

Zach

Just because you have a large turbo it doesn't mean you have to ride around town with your boost set at 20PSI. If you want to street the car around town just turn down your boost down to 5-10PSI (switch to a preset/predyno'd map for this boost level). You can raise your boost back up when you hit the track or strip. I think you can make any turbo setup "streetable" if you're a pragmatist.

:D

https://www.rx7club.com/forum/showth...b&pagenumber=3

and further down the thread from nocab....


"hrmp, hardly tuned would be a much closer statement to the truth, (I had the car running 2 days with a completed fuel system which would
finally hold fuel pressure over the entire RPM range before I made a couple test dyno pulls), over 80 degree's outside, humid as hell, with a
cracked wastegate flange and toasted gasket between my exhaust mani and wastegate, leaking exhaust pressure out like crazy before the
turbo would hardly be called "good" circumstances for high dyno numbers.

I only made two pulls because all I wanted to see was where my peak tq and peak hp #'s fell before I finished tweaking my timing maps.

http://flathat.woodstream.net/RX7/G...1010030-sm1.jpg (what was left of the gasket)

http://flathat.woodstream.net/RX7/W...1010033-sm1.jpg (wastegate flange)

K
hate or doubt, but 500rwhp on the GT35/40 isn't far away, I'll post the sheet!"

just fyi

You ever notice that when anyone posts their dyno sheet they are alwasy dynoing in the worse of conditions..."It was hot as hell and I had molten lava sitting under my oil pan, and no fan was blowing on my rad."

It's like saying..."Even though all the planets weren't aligned, I STILL put down this this much."

Not saying anything towards anyone....Just think it's funny that's all.

hahaha. yeah you're right. I think it's that way with every sport and hobby though.

Well it seem that everyone always gets their car running good enough to dyno during the summer when it's hot outside because they are always spending the winter getting it ready to dyno in the hot ass summer:)

I have thought about all sorts of different turbos and just can't make up my mind on what I want to do with the RX-7. I want it to make more power than 400RWHP on pump gas, and the bigger turbos can make 425-475 @ 15psi, but where i live it rains a lot, and I dont drive fast on the streets, i never hit my 2nd turbo, but I am going to buy a different car to make a drag car, so do I make the RX-7 a high HP car too, or get a smaller turbo and not be as fast as I want to be but possibly be more fun/safer to drive around town. I have had 400+ HP cars before, and only been in the 11's and I want to finally friggin make 10's without blowing a motor. I think the Miata might be able to make 10's, but I dont want to risk blowing the motor, so 15psi is the max I wanna run. Well whatever I have time to wait and decide on what turbo to get since I am going to miss this summers race season anyways. Ill get my car done this winter and be ready for next year.

Some fact to your fiction:
"If you want to street the car around town just turn down your boost down to 5-10PSI (switch to a preset/predyno'd map for this boost level). "

Single turbo external wastegates come with an 11 or 12PSI spring (or higher). This means you have to rebuild the wastegate to get less then 11PSI. The weaker the WG spring the lower your max boost -or- the more unstable your high boost (this depends on the controller).

Stand alone ECU's have different cells for different boost levels. This means you don't need to swich maps just because your running a different boost level. You can run 11PSI or 20PSI just as long as you're running a decent map that adds the appropriate amount of fuel, & pulls the appropriate amount of timing.

A T78 car with a full exhaust at 11PSI it comes on like a switch. A ported motor & full mods will still spin enough at the top of 2nd gear to switch lanes, & that's on dry pavement. It is pretty cool though. ;)

lol. O.K. so that was an exageration but you get the idea. And the MAP issue completely depends on the ECU. ECU's like the infamous purple box have seperate preset maps for predetermined boost settings. I think we're saying the same thing here?

Ice, have you thought about aftermarket twins? I would either: buy a daily driver and soup the 7 up for racing, or build a race car and invest in reliabilty mods for your 7. Keep in mind that the 13b is far from bullet proof.

I made 404hp at 15.5 psi. My boost controller was accidently set for warning to cut boost past 15 so it wouldnt go any higher. I couldnt figure out why until after we got the car home and read the manual on the boost controller. I was running a bone stock mazda reman motor and the GT3540 with the 1.06 A/R. That power peaked at 6k and the Dyno sheet was flowing all over as you can see if you have viewed it on here. I posted it in another thread. Anyways It had alot more potential even with the stock motor. Now I have a Street ported motor going in later this month as well as water injection. I estimate somewhere near 450-475 at the wheels on pump gas around 17 psi. The GT3540 is fast spooling big power making turbo. I get full bost by 3200 rpms. It comes on all at once. I am not sure who stated it comes on gradual. It doesnt. The ball bearing turbos spool fast and as soon as they get enough exhaust. Alot less drag than standard bearing turbos. Makes it good for someone with a stock motor who wants to make sure he gets 400RWHP on pump gas. Great Turbine design. The Garrett GT turbos are the next Generation design. Thats why there is alot of hype. They are new. Make great power and spool faster than typical turbo the same size. That equates to a better power band. More usuable power on the street. Not to mention it uses all new Technoledgy and its the only way to go. I wouldnt trade mine for anything. Ask yourself this. How many guys you see buying this turbo that take it off and sell it because they were not happy with the results?

full boost by 3200? That's actually pretty impressive. Well actually there have been people swaping out the 35/40 for other turbos. If you read the first page of this thread you will see what I mean.
Speaking of revolutionary turbos..when is that electronically assisted no lag turbo supposed to hit the markets? I think Garrett is the company developing it..

Already got 2 daily drivers, and gaining a collection of other cars. I might be young but working at a car dealership in a management position pays decent and you know about buying cars. I dont want hybrid twins, they are good, and make good response, but i want all that crap out of my engine, I would just get a GT3540 over upgraded twins. Maybe I should just get a GT3540 and put a T51R KAI on the automatic supra.