1j vs 1j vvti max power on stock turbos?

[Z2TT]

Hi,

From what I've read, the 1j non vvti's CT12a's outflow the VVTI's single CT15, and many people on Supraforums etc seem to agree.

Just wondering what power levels could you get with both engines before the turbos begin to run out of puff?

Anybody had experience with both engines?

Thanks.

[Azzamk2]

I have been told the same aslong as you get rid of the stock dumps on the 1jz TT, also that the non vvti 1jz can handle abit more power??

[JP]

The CT12a's will last a bit longer than a CT15 if you're running twin dumps, using the same boost on each. The failed CT15's I've seen have had the bearing flog out or the exhaust wheel come apart.

My JZX81 engine made more area under the curve at the same boost compared to my jzx100 engine. Both had upgraded FMIC's and 3" straight through exhausts, running wastegate pressure.
I got the raw data printout from the dyno so I could compare them in a spreadsheet, you can find the results to that here: http://users.tpg.com.au/adsl0uxv/dynoresults.xls
My wagon had the jzx100 drivetrain, chaser was the jzx81.
With a manual JZX100 engine you usually get to about 220kw atw on a Dyno Dynamics in shootout mode before the turbo gives up.

[Cressida25T]

Kudos on the excel graph. You should plot the torque curves for each setup and show that difference - isn't that where the CT15's have the advantage? More pull down low, but less balls out power for the VVTi's. Kinda handy though when it's only a 2.5L

[JP]

the tractive effort readings are the closest thing to torque in the spreadsheet, plotted on the Tractive Effort tab you can see the twin turbo setup has more midrange torque. Both were with R154's.

[Z2TT]

Hi,

JP, Thanks for the graph, it interesting that at the same boost you mention the CT15's have a BETTER curve, this is surprising, shouldn't the VVTI engine have a better curve? Since as many people mention it has more low end power, less lag and comes on boost faster?

[JP]

The VVTi engine definately feels better to drive on the street, from a standing start it's nicer to drive. On a dyno run from 60km/h the difference between the motors isn't as noticable.

[Z2TT]

Then wouldn't one of the power lines be above the other to show the VVTI enginehas more power down low?

I see the purple line which I assume is the better curve and he NON VVTI engine, that line is always above the other line across the whole run, same goes for Tractive effort too. So I'm wondering if the VVTI engine has more down low power how come the dyno doesn't show it?

Or is that because on the dyno sheet, the Yellow line for VVTI engine only begins at 55km/h?

Also up top The Purple line which is the Twin Turbo crosses over with the VVTi engine, does the twin turbo runout of puff up top when it crosses over as the VVTi keeps pushing?

[J0RD0]

my celica made a supposed 373hp on 17psi, stock manifold, turbo and dump pipe. It had 3" exhaust, intercooler and motec and a stock auto! The best thing i remember about the car was suprising the F*#@ out of bikes off the line, got quite a few of them. It was soo responsive i could bring it on boost sitting at the lights! I had the car for about 8 months and drove it quite regularly mainly always on 17psi (9psi was reserved for the rainy days) Never had a problem with the turbo and felt like it had more in it.

[Z2TT]

Surprising seeing as i have been told by a shop that hiflows these, and generally by people on forums its agreed that max is about 225rwkw (300hp) from the ct15.

[J0RD0]

Its funny cause i was at a mates place and this guy rocked up in another ra23 with a non vvti 1jz to buy some parts and he had a 35/40 custom manifold, shift kitted auto, basically the works and it was tuned @ 16psi and was making a supposed 360hp atw. So i hit him up to take me for a spin thinkin this thing is going to be wild. We went for a lil drive and old mate gave everything it had and to be completely honest it felt the same as mine if not the tiniest bit slower. I got his number and spoke to him later in the week because he went to willowbank to do a run and the best he got was a 12.01, and that was with semi slicks. Ive run a 12.4 with 225 street tyres, stock turbo, stock auto and stock stally.

Another example is when i went down to sydney last year right before i sold my car i met up with Jase (smokey228) and had a couple of runs against him late one night and you can ask him if you dont believe me but i was on 1 maybe 2 car lengths behind him, not bad for a stock turbo'd 1j with a stock auto against something that had 35/40 and 20psi and his was manual with a twin plate.

You know i was pretty skeptical about mine pulling a legitemate 373hp on a stock turbo (some dyno's read more than other's) but 2 other examples of non vvti 1j's with 35/40's sort of makes me think otherwise.

Sorry about that rant but in my experiences 1j vvti FTW!

[AL510]

Based on your mph in your sig, it seems a little low for that sort of horse power.

My hilux with a 1uz and nitrous made a best of about 320 at the wheels and on a dyno jet and ran a best mph of 113 with a heavier car.
In drag racing circles your mph is considered to be a true indication oh horse power.

Al.

[JZA70 R]

Jordan, ive run a 12.4 @ 111mph and id say my car is substantially heavier. Mine only makes ~320rwhp on the rollers... so id say 373 is optimistic...

the reason why you keep up with the single turbo cars is because they have less power under the curve + lag and you dont.

my car pulls away from another 370hp single turbo supra but its because i have so much more horsepower under the curve...

[Z2TT]

JZA70 R but if that supra you pull away from has more max power, wont he eventually catch upto you and beat you when he reaches max power at a very high speed?

[JZA70 R]

that depends on a lot of things, but the short answer is yes. however in my instance no.

both cars were actually run on the dyno at a dyno day, my car made 315rwhp and his made 366rwhp. we even have same gearbox and diff ratio's. same motor too.

We raced from the top of 2nd gear to the top of 4th and we were basically neck and neck with my car pulling away ever so slightly. maybe somewhere during 5th gear he would start to catch up while the engine was in the powerband where it was making more horsepower, but if it was a race to 400m mine would have won the race.