Re: Did 15G's ever trap 126mph?
The old days yes
when everything was pretty much stock except a few boltons and (now crappy) HKS VPC for fuel control. I remember 1994 when HKS California importer had ceased selling VPC's for 3S. Robert O'Toole was there I think, telling me he would NOT sell me a VPC for the 3S unless I agreed NOT to try returning it WHEN it didn't work properly on my car. I agreed because it was the only way and I thought I knew how to fix it to work...well that opened up the car bigtime and let me FINALLY get past the devastating ~16psi fuelcut which had basically put an absolute HP limit on our cars up to then. Now, fuelcut as a problem? LOL we have many computers and piggybacks to get past THAT old stuff!
The 15G's I had were a little special in that they had a slightly larger turbine wheel, in the slightly bored-out TD04-13G turbine housing. That was a secret then
The problem I was having was that the small td04 centersections just were NOT built for nor up to the task of holding higher boost (24+psi, up to 28+ on spikes and with NOS) and the thrust bearings would wear, the turbos would start to leak oil and huff smoke out back as the wear got bad. So, I wanted to get out of the TD04 family badly.
Mitsubishi-built "sport turbo" 13G's were dead reliable; the same turbos modified to 15G were good too but I think I rebuilt them once due to wear; then modded them to 17G size and I think they wore out twice pretty fast, just not so happy at high boost with NOS etc. kinda overdriving them.
13G's outstanding turbos, worth 50hp more than stock all else equal; 15G's great and more hp than 13G's; 17G mod was not happy due to longevity issues, and really didn't get much if ANY more hp/mph out of the 17G's...but confounding factor was odyssey of Web Cam regrinds with Kibblewhite Precision Machine upgraded valvespring setup they claimed was fine to .600" lift but I kept breaking outer valvesprings, wearing valve tips and rockers...finally measured the coilbind MYSELF and the freaking things were .030 from coilbind at the lift I was using, so finally fixed that but had been running on broken valvesprings, slightly tweaked/bent valves, wearing cams etc for like 2 years with the 17G's so maybe never realized their full potential.
For my HP estimates through the years (when not on dyno), I used the trusty Moroso Power Speed Calculator sliderule, Moroso part number 89650. You enter the vehicle's speed and weight, and it gives HP. You can enter in any 2 data, including hp, weight, ET, trap speed, weight/power ratio...and get out the other data. It assumes a fairly ideal launch for the ET.
For Matt's current 9.0 @ 157mph at 2920 lbs, gives ~860hp. All in all, pretty close to what 3SX and Matt are likely making. 3SX going 152mph gives around 790hp...so my calculator may be a conservative dyno estimate
Way back then I didn't have much weight out, so was around 3850 lbs race weight (stock car was 3780lbs, I had a little over 100lbs out of car, so right around 3850 lbs). 125.76 mph at 3850 lbs was about 580hp.
If my car weighed 2920 lbs back then, it would have been going about 138mph
not too bad no NOS on 15G's.
When my 94 went 10.4 @ 138.76, it had dyno'd about 740hp with 50hp NOS jet. I used 75hp jet to do the 10.4, and Moroso sliderule with mph and weight (3680 with me in it, car is now around 3500 without me, has rollcage etc) says ~770hp. Pretty close! Certainly differences of +/- 10-20hp can be seen, and these are ESTIMATES.
If my 138.76mph 94 VR4 weighed 2920 lbs like Matt's, it would have gone about 151mph...so yes that 760 lb weight loss of Matt (and the 3SX drag car) make a critical difference, and explain why my street car/roadcourse car will never dragrace as quick/fast as them again.
But, you WILL see me driving my car to work again tomorrow, just like I did at Road America HP driver event Oct 14-15, and to buddy's house to watch the Packers beat Denver today radio on, power windows and all
Anyway, the "old turbos" were not bad, just had their performance evelopes. As for 19T's, if you have the compressor map you can SEE if/how much better they might be. The problem with the 14B wheels is their "B" design is less efficient at higher boost levels than G or T wheels. B are great low/midboost turbos, but may not be AS IDEAL at higher boost levels. The T comp wheels I have not used nor do I know their pressure ratio capabilities. More airflow can be great, but with only 3 liters you will need more BOOST to put those lbs/hr of air into the motor.
I like the idea of bigger compressor AND HOUSING than the stock TD04 or 15G, but I have questions about the longevity of the TD04 center at higher boost levels; I'd prefer to get out of that series and into at least good but cheap EVO3 turbo setup if at all possible, for most people. I am sure Dynamic, 3SX, IPS et al can direct better than I, but I do NOT trust those tiny TD04 centersections at high boost.
Your Results May Vary!
Jack T.